Oh boy... I'm not sure how to comment on the above post.
The ECU doesn't "learn octane" before you're out of the driveway. It's got a IAM which slowly increases timing based on load until it reaches a knock, and then retards.
The ECU doesn't "learn" during full boost.. at that point you are in an open loop map, and the ECU is running specifically off a MAP and major sensors.. it doesn't actually learn anything at that point. So if your car is specifically revving up to burn off excess fuel, then it's programmed into the map to do so... But because this is not a Drive By Wire car, then this is not possible..
On a Drive By Wire car... there is a throttle position sensor that determines how far down your pressing the accelerator pedal... this determines how far to open the actual throttle. This can be intervened by the computer, because the computer controls the whole process. But on a Drive By Cable (or Drive By Throttle as it's also known) (02-05 WRX) the throttle position is DIRECTLY related to the cable being moved by the accelerator pedal.
So, unfortunately, even though your thinking sounds legitimate.. it's not
I still maintain my reasoning as described before.