Welcome to FT

I have seen this reported many times on FT. Just because it makes sense to you and I, doesn't mean it will to Marriott. You can try contacting the hotel sales manager and see if they can help you out.

You can also try and get a LNF rate for all the nights you need that way you stay where you want and screw them in the end.. hopefully with a lower rate than what you originally proposed

You can post your LNF request for assistance here:

http://www.flyertalk.com/forum/showthread.php?t=789113