Harsh Mid-Range Timing Pull?

I am having extreme difficulty in completely eliminating knock and heavy timing pull in the mid-range. I had my intake cam retarded by 2 degrees and my exhaust cam at stock, now -4 and -2 degrees respectively, and part load fuel has been bumped up and ignition cut back a few degrees but nothing seems to be working. I've got total cumulative timing pull exceeding 40 degrees at times between 2400 and 3800. I basically have no real pull until the engine spins around 3800 rpm then it just unleashes hells fury. I've dug around but nothing seems to pop out and scream "idiot" at me. I run quality, 93 octane(US) and it doesn't appear to be boost related because I'm not in boost yet when it starts to pull timing. I'm at a loss here. Once I crack that 3800 point, though, the tires can't quite hold all the power down. I'm running peak boost pressure at 18PSI with a MBC on a 15g but I don't spool until 35-3600 thanks to the timing pull.
Here's the RPM vs Load vs Timing pull table on running average in excel.