I have two reservations in the Marriott system where I used points to redeem free stays:
Interestingly, one of the reservation I had points already taken from my account at 15,000 (point saver rewards) per night for a total of 195,000 points (Category 4) on a 16-night stay (including 3 fifth nights free). Today that same reservations reflects 20,000 points per night, but the 195,000 points were still being used to cover all 16-nights instead of the 260,000 points required under the new points redemption policy (the reservation begins Late May 2018 and runs through Early June.
Now my second reservation was set for Nov 2018, also at a Category 4, originally booked with Point Saver rewards (15,000 per night with 5th night free) when I made the reservation at the beginning of 2018. I was only staying for 5 nights, so 60,000 points was the original reservation confirmation total. I was just short of the 60,000 points in my account when I booked the reservation, so it was accepted under the proviso that I would get the points within 2 weeks of my stay which would not be a problem. I could have (and now think I should have) transferred points from SPG or United to cover the small shortage. Now, that reservation is 80,000 points, the 15,000 point saver is no longer available or the new system just kicked in the peak rate rule on me since it will be after the August changes. I'm not sure, but it really doesn't matter much anyway. I still get the fifth night free for 80,000 points, but the stay is now 20,000 points more that it should have been. Oh well; but I wonder if I had paid for the stay up front with points would Marriott have honored the original reservation? Hmmmm. I'm not sure. Not a big deal, but thought worth sharing.
It make me wonder if under the new system of Peak and Off Peak points redemption values, perhaps it is better to always book and redeem points immediately for a stay just in case a property is suddenly moved to Peak period vice off-peak period for a reservation. I guess this is something to watch for under the new system rules. Perhaps this is a question to added to o0o0o0o0o0o...points! historic one-stop Q&A list? How often are peak/off peak periods determined and who determines them: Marriott, the Property; once a year, ad hoc, whenever capacity surges, etc? o0o0o0o0o0o...points!, what do you think? communitymanagers have pretty much said more information is coming, so be patient and wait for details. Probably not worth the additional inquiry at this point.