When my car was originall "tuned" and i paid hundreds of dollars for, When I brought my cable and downloaded the rom, it was identical to stock, except for a few warning lights turned off, and my boost tap was turned up. :
I was pulling fuel all over the place, not to mention this was after a new motor swap, new turbo, new injectors, new pump etc, and none of that was compensated for...
Now my iv'e retuned myself, with some guidance from another tuner, and haulin ass even more.. ;D closed/open loop i think took me like a couple of weeks of driving to dial in.