To be certain you need to ask the property. Logically, I think for every three nights of your stay you could earn 500 points. E.g. 250 points/night for two nights, 0 points the next night when your room is cleaned by housekeeping, and wash, rinse. repeat through your stay. Since 20 nights isn't an even multiple of 3, you may only get 250 points the last cycle rather than 500 since they still will need to clean your room after you check out. 6*500 + 250 = 3250 points by my calculations. Again you need to ask the property to see what they will actually do. Good Luck!

--Jon