Mark I don't use any treatments on cars that are still under warranty. Simple reason is I've not seen additives on service schedules. Although the Forte rep sells cases of the stuff locally to Fiat, Vauxhall, Seat dealerships. Most of the cars I see are usually out of the warranty period. So I use the UKAT service schedule and add the treatments. I regularly turn away new cars looking for servicing on the basis that I don't need the grief and the runaround from the dealers when the car goes to the dealer for warranty repairs...
Paul.