Based on my experience with the 6.4Ls--I've had 2 of them lose a piston--I would be very concerned about what is the cause. Both of mine were deleted, and no use of the performance levels of the tuner.
You should probably have a diagnostic run on the firing effectiveness on each cylinder--that will tell you if any of them is losing compression.--couple of hundred $$ for tech time. You might head off some trouble, or figure out if you need to be trading it off.
Also, much info on the 2008-10 6.4s on:
www.thedieselstop.com