Found the culprit! The 12" silicone hose would constrict when the boost got higher. When it was hot you could easily squeeze the hose. So I cut it in half and replaced it with a hard pipe. Wow what a difference! Now it's back to pulling like gangbusters again! I could have avoided all the headaches and gone out and spent hundreds more for the Needswing, but that would take away my DIY fun factor! I'm learning a lot about the car, that's for sure, and enjoy playing with it along the way! I guess I'll have to go back and dyno it again to get accurate readings.

P.S. Let this be an educational lesson, just in case you encounter the same type of problem I did with car holding at high boost.