Okay, next piece of the puzzle... So I went to buy stabilizer, and while I was there I decided to have them test the water just for fun... I told them I didn't think I had any CYA and he looked up my results and said that the last 3 tests were 100, 100, and 80 (way above what I was showing) so that I was decreasing and that might make sense. So I'm standing there while he does the test and he says, yeah you don't have any CYA. but then the other employee leans over and says no, he's got lots of CYA... then they start to argue and get confused... Next thing you know they write down 80 as my CYA number... 80! After close to zero to start with... So there you have it, anecdotal evidence that CYA testing at pool stores is a crapshoot...
Needless to say I bought stabilizer and more reagents to do my own CYA testing and I'm doing the sock method as we speak.