I think you should find another dealer.
BMW incentives are applied "after" your best-negotiated-price.
I have noticed that some things are designated on the bill of sale as a rebate (i.e. Holiday Cash + Loyalty credit) vs. others (Eco-credit, USAA credit) come off the "Delivered Price of Unit". I think this just means the dealer has to submit to get their money back one way, vs. another.
2016 M3 - current
2013 ActiveHybrid 3 - sold
2012 M3 coupe - sold