Oops,

# Keep the last 5.
if (@sets > 5) {
   @sets = @sets[-5..-1];
}
[download]

should be

# Keep the first 5.
if (@sets > 5) {
   @sets = @sets[0..4];
}
[download]

It's a remenant of an incorrect version I wrote before posting.

(I updated my earlier post to remove the error.)