This is my view on this topic. It is based on what I have been told over the years. The AP is fixed. There is no discount on AP. A dealer will get a fee for taking an order of a car on the motability scheme. Latest figure I have is £400. From this fee the dealer can offer cashback offers. I have been told £400 is what is paid to all dealers but have heard of dealers giving £500 cashback etc. Maybe they earn more through car sales or servicing etc.