rel3rd
TunedByFrost supporter

That's odd. I literally did a mild tune on my neighbor's truck less than a week ago. Downloaded stock tune, bought 2 credits, got my new app key, modified tune, and reflashed. No issues and nothing looking different than before. I'll have to look around on their forum when I get some free time.

This thread is older than me, but you do not need to take any classes to be able to unlock anything or be allowed to tune your truck or car. If the vehicle calls for 2 credits, then using those 2 credits will get you a new "application key" and let you "tune" an unlimited amount of times.