Thanks for the update tpspeier. (I think Chem geek thought I was the OP). So maybe the differing results are related to the absolute CYA or FC levels or their ratios?

Your original CYA was 110 - 120 and now is 40. Original FC was 8.5 or 11 (without or with speedstir respectively). What's you current FC at CYA = 40?