So the latest news on the AEM FIC is that there is a limit to the amount it will retard the ignition. The limit is
Around 38degrees. There was a post on the AEM Forums from a use who was wondering if you could retard the ignition by 710degrees to get 10 degrees advance. The answer is no.
If you want to use the AEM FIC to advance ignition you have to advance the base timing of the car. And then to get the timing back to what is was previously use the AEM FIC to retard the ignition everywhere.
When you want to advance the timing is a specific area of the map you simply reduce the retard that the AEM FIC has in the specific cell.
Advancing base timing can be easy or hard. Depends on the car. Best to consult a service manual for your car or to check out forums