Funny, I recently ran into this issue at a Homewood Suites. I booked a 1 bedroom, since that was what was available with points, but with 4 kids we would prefer 2 bedroom. Armed with the price differential of 190 vs 270 cash, I asked if I could pay to upgrade. The woman told me its a different room type not an upgrade (petty wording difference if you ask me). She said they can shift room types but its 279 a night for the swap. I said thats more than the cash rate, and she said its the best she could offer.