Stroker Performance Review

Could you explain this to me. It says 390 per inch so wouldn't going from 1.9 to 1.8 increase it by 39lbs or is there something I am missing or not understanding?

if it were 390 per inch, at 1.9 wouldn't it be almost 770 ish...lol
Something in the equation is off
Well we discovered that the throttle wasn't opening all the way by a half an inch or so.. defnitely enough that it was squiring gas in that last bit. Thought we had that right but doing so many things. Not saying that is the problem but definitely a positve step.

good find.... likely a few hundreds