I'm not sure thats how marriott works exactly... rollover nights don't keep rolling over. If you did 200 one year, and 150 rollover; doing 0 nights the next year would have 0 nights rollover. I could be wrong, but thats how I thought it would be.

There are a ton of plats, and i think this would further devalue the program, if granted on a 1:1 basis. I don't think that doing fractional rollover would be a bad idea, maybe at a 2:1 ratio, so 100 nights (or 50 extra) rollover 25 (for one year only).