my $a = "x";            
while ($a ne "y")
{
    ...
    chop $a;
}

##</code><code>##

unless ($files[0]){
    print "\nSorry, no xml file(s) in script folder\n\nScript Terminated...\n\n";
    }
    else{
	...  # a gazillion rows
}

##</code><code>##

unless( scalar @files ){
  warn "no files";
  exit;
}
...

##</code><code>##

parse_file($_) for @files;

##</code><code>##

foreach my $i ( 0 .. $count ){

<li> to be more explicit (since you want an array), do <c>unless( ref($doc->{$sub1}) eq 'ARRAY' ){
##</code><code>##

foreach my $sub1 ( sort keys %{ $doc } ){

  ... # $sub1

    foreach my $sub2Hash ( @{ $doc->{$sub1} } ){

        for my $sub2 ( sort keys %$sub2Hash ){

            unless (ref($sub2Hash{$sub2})) {

                ...  # $sub2
                $worksheet->Cells($rowCount, $colCount)->{Value} = $sub2;
                $worksheet->Cells($rowCount, $colCount)->{Value} = $sub2Hash{$sub2};
                next;

            }

            foreach my $sub3Hash( @{$sub2Hash{$sub2}} ){

                for my $sub3 ( sort keys %$sub3Hash ){


##</code><code>##

sub __add_non_array {
  my ($worksheet, $rowCount, $colCount, $sub) = @_;
  $worksheet->Cells($rowCount, $colCount)->{Value} = $sub;
  $worksheet->Cells($rowCount, $colCount)->Borders() -> {Weight} = 2;
  $colCount++;
  $worksheet->Cells($rowCount, $colCount)->{Value} = $doc->{$sub};
  $worksheet->Cells($rowCount, $colCount)->Borders() -> {Weight} = 2;
  $rowCount++;
  $colCount--;
  return ($rowCount, $colCount);
}

while( my ($sub1, $aoh1) = each %$doc ){

    unless (ref($aoh1) eq 'ARRAY') {
      ($rowCount,$colCount) = __add_non_array($worksheet, $rowCount, $colCount, $sub1);
      next;
    }

    foreach my $sub2Hash ( @$aoh1 ){

       while( my ($sub2, $aoh2) = each %$sub2Hash ){

          unless (ref($aoh2) eq 'ARRAY') {
            ($rowCount,$colCount) = __add_non_array($worksheet, $rowCount, $colCount, $sub2);
            next;
          }

            foreach my $sub3Hash ( @$aoh2 ){

                while( my ($sub3, $aoh3) = each %$sub3Hash ){

                  unless (ref($aoh3) eq 'ARRAY') {
                    ($rowCount,$colCount) = __add_non_array($worksheet, $rowCount, $colCount, $sub3);
                    next;
                  }

                    foreach my $sub4Hash ( @$aoh3 ){
                        print "Collecting general information...\n";

                        while( my ($sub4, $aoh4) = each %$sub4Hash ){

                          unless (ref($aoh4) eq 'ARRAY') {
                            ($rowCount,$colCount) = __add_non_array($worksheet, $rowCount, $colCount, $sub4);
                            next;
                          }

                            print "Collecting $sub4 ...\n";

                            $subDataRow = scalar(@$aoh4) + ($rowCount + 1);

                            my $worksheet = $workbook->Worksheets->Add({After=>$workbook->Worksheets($workbook->Worksheets->{Count})});
                            $worksheet -> {Name} = $sub4;
                            $worksheet -> Range("A1") -> Font -> {Size}= 14;
                            $worksheet -> Range("A1") -> Font -> {ColorIndex}= 2;
                            $worksheet -> Range("A1") -> {Value} = "$sub4";
                            $worksheet -> Range("A1:E1") -> Merge;
                            $worksheet -> Range("A1:E1") -> Interior -> {ColorIndex} = 25;
                            $worksheet -> Range("A1:E1") -> Borders() -> {Weight} = 3;
                            my $subDataCol = 1;

                            foreach my $sub5Hash ( @$aoh4 ){

                                my $temp = "";

                                while( my ($sub5, $aoh5) = each %$sub5Hash ){
                                    my $curID = $sub5Hash{enclosureNumber} || $sub5Hash{number} || 0;;
                                    my $nextup = "";

                                                     if(ref($aoh5) eq 'ARRAY'){
                                                     #################
                                                     # SUBINFORMATIE #
                                                     #################  $sub 4 is rank $sub5 is attribuut van rank $sub6 is element binnen rank eg arrayref

                                                         foreach my $sub6Hash ( @$aoh5 ){

                                                                 # Nieuwe ArayRef, ExtentbyVol,StorageDeviceFRY (nieuwe titels maken

                                                                 if($nextup ne $sub5){
                                                                     $new = 1;

                                                                     $subDataRow++;
                                                                     $subHeaderRow = $subDataRow;
                                                                     $subDataCol=1 ;
                                                                     $nextup = $sub5;
                                                                 }
                                                                 else {$new = 0;}

                                                $subDataRow++;

                                                              while( my ($sub6, $val6) = each %$sub6Hash ){

                                                        # subinfo title on new element
                                                        if ($temp ne $curID){

                                                            $temp = $curID;

                                                            $worksheet->Cells($subDataRow, $subDataCol)->{Value} = "$sub4 : $curID";
                                                            $worksheet->Cells($subDataRow, $subDataCol)->Interior->{ColorIndex} = 33;
                                                            $worksheet->Cells($subDataRow, $subDataCol)->{Font}->{Bold} = 1;
                                                            $worksheet ->Cells($subDataRow, $subDataCol)-> Borders() -> {Weight} = 1;
                                                            $subDataRow+=2;
                                                            $subHeaderRow = $subDataRow;
                                                            $subDataRow++;
                                                        }

                                                        # Header
                                                         if($new){
                                                            $worksheet->Cells($subHeaderRow, $subDataCol)->{Value} = $sub6;
                                                            $worksheet->Cells($subHeaderRow, $subDataCol)->{Font}->{Bold} = 1;
                                                            $worksheet ->Cells($subHeaderRow, $subDataCol)-> Borders() -> {Weight} = 2;
                                                            $worksheet ->Cells($subHeaderRow, $subDataCol)-> Borders() -> {ColorIndex} = 25;
                                                         }

                                                            $worksheet->Cells($subDataRow, $subDataCol)->{Value} = $val6;
                                                        $subDataCol++;
                                                                     }
                                            $subDataCol=1;
                                                             }
                                                     }

                                                     else{  # aoh5 is not an array

                                                     ###################
                                                     # MAIN INFORMATION#
                                                     ###################


                                                         # Index, if any of those, will be placed in first column
                                                         if ($sub5 eq "number" || $sub5 eq "id" || $sub5 eq "enclosureNumber"){
                                                             $worksheet->Cells($mainHeaders, 1)->{Value} = $sub5;
                                            $worksheet->Cells($mainHeaders, 1)->{Font} -> {ColorIndex} = 25;
                                            $worksheet->Cells($mainHeaders, 1)->{Interior} -> {ColorIndex} = 15;
                                            $worksheet->Cells($mainHeaders, 1)->Borders() -> {Weight} = 2;
                                            $worksheet->Cells($mainHeaders, 1)->{Font}->{Bold} = 1;
                                                      $worksheet->Cells($rowCount, 1)->{Value} = $aoh5;
                                            $worksheet->Cells($rowCount, 1)->{Font}->{Bold} = 1;
                                            $worksheet->Cells($rowCount, 1)->Borders() -> {Weight} = 2;
                                                         }

                                                         else{
                                                             unless ($worksheet->Cells($mainHeaders, $colCount)->{Value}){

                                                                 $worksheet->Cells($mainHeaders, $colCount)->{Value} = $sub5;
                                                        }

                                                    if ($sub5 eq "wwpn"){
                                                $worksheet->Cells($rowCount, $colCount)->{NumberFormat} = "0";
                                                $worksheet->Cells($rowCount, $colCount)->Borders() -> {Weight} = 2;

                                                    }

                                                             $worksheet->Cells($rowCount, $colCount)->Borders() -> {Weight} = 2;
                                                             $worksheet->Cells($rowCount, $colCount)->{Value} = $aoh5;
                                                             $worksheet->Cells($mainHeaders, $colCount)->Borders() -> {Weight} = 2;
                                            $worksheet->Cells($mainHeaders, $colCount)->{Font}->{Bold} = 1;
                                            $worksheet->Cells($mainHeaders, $colCount)->{Font} -> {ColorIndex} = 25;
                                            $worksheet->Cells($mainHeaders, $colCount)->{Interior} -> {ColorIndex} = 15;
                                            $colCount++;
                                            $LastRow = $worksheet->UsedRange->Find({What=>"*", SearchDirection=>xlPrevious, SearchOrder=>xlByRows})->{Row};
                                        }
                                    }
                                } $rowCount++;
                                  $subDataRow++;
                                  $colCount=2;
                                  $worksheet -> Range("A:X") -> {Columns} -> Autofit;

                            }
                              $subDataRow=$rowCount+2;;
                              $colCount=2;
                              $rowCount=4;

                        #Seperate general information on first sheet.
                        } $rowCount=4; $colCount+=3;
                    }
                } $rowCount=4; $colCount+=3;
            }
        } $rowCount=4; $colCount+=3;
    }
}

##</code><code>##

  foreach my $sub2 ( sort keys %$sub2Hash ){
    my $aoh2 = $sub2Hash->{$sub2};