my $name1 = 'name1'; # or whatever
my $name2 = 'name2'; # or whatever
my $sum = 0;

# turn Hash of Arrays into Hash of Hashes
my %HOH;
while (my($name,$aref) = each %{$VAR1} ) {
    for my $item (@$aref) {
        my($prop,$score) = split(',',$item);
        $HOH{$name}{$prop} = $score || 0;
    }
}

my $first  = $HOH{$name1};
my $second = $HOH{$name2};
while (my($prop,$score) = each %{$first} ) {
    $sum += $score if exists $second->{$prop};
}
print "Sum of $name1 in $name2 is: $sum\n";

# Prints:
Sum of name1 in name2 is: 8.5889
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