Evaluation of Bollworm Management in Bt Cotton

I am researching to validate the current bollworm threshold found in the Mississippi State Insect Control Guide to see if the current threshold of 20% eggs and 5% damage needs to be lower (more strict) or if it can be raised and still have the same if not better yields. I am also looking at weekly sprays to see what week after bloom you could terminate pyrethroid sprays and have the best cotton yields.