I'm a little unclear on how credits are used.
The impression I've received (after already purchasing the VCM suite, though I've not yet activated it) is that every time I modify the tune and flash the vehicle, it takes a credit. (This is for an 06 Solstice 2.4, to which I've just added a turbo.)
Is it really true that each and every tune change I make - specifically, I'm tweaking injector parameters - takes a credit? That seems a little excessive considering the suite was $500.