Hi,
First, here is the image:

Stamp is listed in Scott as Perf 12, 11, 12.5, compound and imperf pairs, but nothing listed as perf 13.5.
It is definitely A22, and definitely perf 13.5 (I use a Sonic Imagery perf gauge). I'm wondering if this is just a Scott omission.
Any ideas out there will be appreciated!
Thanks, Ray