Perforations ... Uggh!

This one has always bugged me, ever since I posted in a Labuan thread, https://goscf.com/t/29499. For the life of me, I can't figure out the perforations, and probably because it falls into that infamous, Perf xx-yy category, meaning that the perforation could be anything from xx to yy, and all varied in-between. In addition, Stanley Gibbons offers an option for a compound perforation, meaning that all (4) sides could be anything indicated.

Image from the Original Thread:



Luckily, Wert and Nitrolures intrigued me with the 600 dpi perf e-gauge in a previous thread (https://goscf.com/t/39389, and I practiced enough to be dangerous. Unfortunately, it is not so simple.

All of the following are estimates, based on first and last perf, and counting the perfs in-between. As you can see, it is pretty ugly. The top perf appears to be about 13.5:



While the Bottom (12.3), Left (13.2) and Right (13.2) Sides are shown below:







I think this qualifies as Stanley Gibbons 92b, which is described as Perf 13 1/2-14, comp 12-13.

Comments?

I have a few of this kind of horror from Latvia and early Egypt. I would plump for "compound perfs." Some of them, just like your example, defy categorisation and are inclined to give me either indigestion or a headache.