I think we're not replying because we can only guess along with you. I am actually noticing this year that my CYA isn't increasing at the rate it has in previous summers, and in my case it definitely can't be becuase of rain.

I think the best thing to do is start with the premise that you clearly have enough CYA since your chlorine is holding and at what is probably an appropriate level. If you are showing 30 then even if you are off and higher than that, you can look at the chlorine chart and figure that for 30-50 CYA you should be maintaining 3-6 ppm of chlorine. Sounds like you're right there, but re-testing in a few days may give you some peace of mind.