So, spoke with my ticket rep today, who assured me that if I had 4 tickets in 2016-17 I'll be able to buy 4 comparable tickets in 2018-19, no matter whether I buy zero, 2 or 4 for 2017-18 at Allstate. She did point out that if I don't buy in 2017-18 I break the continuity for years as a season ticket holder, which effects priority point total, and where you will actually be able to sit (along with how big of a 'mandatory donation' you want to make). I've plenty of points so that doesn't worry me.
She did confirm that at Allstate, and the new WRA, you will get a time window based on your points to go on-line and pick where you want to sit from the seats available at that time (similar to what MSU does when they do their 'seat adjustment' every few years.
I did suggest to her that it might be good to put out an 'official' communication to clarify this to everyone - not sure how far that will go.
Charcat had a conversation with a different ticket rep and got the same answer. So, if all your points come from longevity as a season ticket holder you probably want to buy at Allstate to maintain your points. If you've got plenty of donation points maybe less of an issue.