If you have a split stay and have the DP for each, you'll get 2 mugs and you'll have to use up the credits from the first part by MN on the change day else you'll lose them. I understand this is an issue with the MB because they bands may change to the new room and orphan your DP credits. The other issue is if it's a split stay but matches up,
DVC often combines those into one reservation. I agree Bill that a split stay or multiple rooms gives you some flexibility that you wouldn't have otherwise. For this situation we often would get it for one but not the other depending on specifics with the largest variable being time of arrival and departure from WDW assuming the group makeup and other choices are reasonable for the DP at all.