FWIW, I agree with CPRich's interpretation. One has to keep in mind two things:

1. If your stays are exactly at a 12 month interval and will only count up to the requisite 50 or 75 nights for a few days, then there is the chance that when the MR program looks back at the last 12 months, it may not catch your 50 or 75 nights. Make sure that you have 50 or 75 nights in the previous 12 months for more than a two week period and it should work fine.

2. This is an unofficial policy, and as such you can't complain to anybody and it could disappear at anytime for any reason. One reason could be that people start viewing unofficial policies as a sense of entitlement. If I were Chris and other MR Execs reading this thread I might well come to the conclusion that this trial/unofficial policy has opened up a whole can of worms that they don't want to deal with; and they may decide to get rid of it like they did the original rolling 12 month program back in the late 90s.

My advice is be grateful for both this unofficial policy and Chris's participation on this board, and don't cut the qualifying nights too short and the unofficial policy should work for you.