I ordered mine today and got invoice using the $1,500 USAA credit. I could have tried to get it lower but I was happy with the price given that I made a phone call to the fleet manager at the dealership close to my house just today and a half hour later I was at the dealership and 20 niuntes later I was back in my car going home with my production number.
He told me before I came that he might be able to give me a couple of hundred more off but I decided not to pursue it and use it as a "good faith" credit with him and the dealership for some things down the road. He is going to give me $450 in golf certificates at a nice golf club nearby so if you include that, I did get it below invoice. lol