Hmm, well for sure the diameter measurement is okay as I double checked a bunch of times after the inital wrong measurement. The scale is not the fanciest thing as sometimes you can turn the knob to zero it and it will really still be zeroed at -1 lbs or whatever, but no matter what the zeroing was it did move up 4.5 lbs from what the stuff the cymbal was balancing on weighed (tried multiple times). I just tested it with some barbell weights and it was reading those alright too.
I got the extra light/thin designation from this thread.
Hmm, if I get the chance I guess I can easily try to borrow someone else's scale or something just to be 100% sure. Is it just that even a super thin 22 should still weigh more than that?