I've ordered a 2016 BMW435i Convertible. It's getting built and will be getting the delivery in end of October or early November. The price has already been fixed at $500 over the invoice price with the dealer. Now I just came to know that BMW is offering $1000 as option Credit. What is that. Can I use it now to negotiate with the dealer and get the car $500 under the invoice price. I haven't given any deposit or anything to the dealer yet. Also is $500 over the invoice price a good deal.