sub order_of_sorted {
    my ( @num, @suff );
    for( @_ ) {
        m/ \A (\d+) \. (.*) /x or die "malformed data";
        push @num, $1;
        push @suff, $2;
    }
    sort { $num[$a] <=> $num[$b] or $suff[$a] cmp $suff[$b] } 0 .. $#_;
}

for my $outer ( ( values %hash )[ order_of_sorted keys %hash ] ) {
    for my $inner ( ( values %$outer )[ order_of_sorted keys %$outer ] ) {
        # ...
    }
}

##</code><code>##

   for my $inner ( ( values %$outer )[ order_of_sorted keys %$inner ] ) {
   #                        ^^^^^^^ Correct.                ^^^^^^^ Oops.