After I purchase the interface, according to the HPtuner site, I need to purchase 2 credits to tune my engine ('07 Chevy 6.0). Will those 2 credits allow me to make changes any amount of times I choose for this particular PCM or are those 2 credits only for a one time change to this PCM? I will only be using HPtuner for this engine. I have no need to tune other engines/vehicles. Thanks
