Once you get the max-out email on a rating, you can drop his minutes to 0 and it will lose points extremely slowly, no more than 2 in a season, usually about 1, and sometimes 0. This has been my experience in every case, regardless of WE. I must admit, I've not had experience doing it with very low WE (under 25 or so), since they are more rare, and among them, they have trouble maxing.