Originally posted by forcedinduction
Exactly, so advancing the base timing will in effect advance all the timing maps.
That's exactly what will happen on an OBD-1 car.
However.
The OBD-2 ECUs have a learning capability. It will eventually figure out that the timing has been advanced and make corrections in the signal sent to the ICM to make sure that the actual timing map is what gets carried out. The way to get around this is to cut power to the ECU every time the car is turned off. There are a couple of ways to work it out, but it's not really worth it just to advance the base timing maps a little bit.