the dyno is giving you a plot of rpm/hp. It is not showing how much fuel is flowing to accomplish said HP, nor is is showing throttle response based on letting off alittle then nailing it for a corner.
I think you guys are both correct
It may not increase max hp or rpm but it could increase throttle response and/or fuel consumption.
I do know, neither JP nor Grinder would add something worthless to your engine, measurable or not
This thread is awesome, love modding discussion. I have sooo much to learn.