Help me on the Timing on Earning Preference Changes?
 

After I complete the 25 nights for the MegaBonus promotion, I want to switch my earning preference from points to miles and start getting stays under the MegaMiles promotion. I don't want to make this change, have my 25 night stay counted as one stay for MegaMiles, and fail to get the 50K bonus points for the 25 nights under the MegaBonus promotion. Any experienced insight on the timing of when to make the change to my earning preference would be greatly appreciated.

Simply wait until you see the MegaBonus points post. It will happen right after the property posts your nights stay credit to MR. Typically it takes a couple of days after you check out.

Thanks for responding, but I guess I wasn't clear.

What I'm asking is to see if anyone has any experience switching their earning preference before a previous stay posts to the MR account. I'm hoping what matters is what you're signed up for when you check in and/or check out. I want to go from another Marriott property on day 26 or 27 after getting my 25 nights under the MegaBonus promotion. Otherwise I have to wait a week before I can start working on my stays for the MegaMiles promotion and I might not have enough time to max out on it.