Many customers seem to be concerned about or misunderstand 1) the subscription and 2) the two year fallback license.
You are already offering a monthly option and a 1 year subscription discount, so would it not be easier to add a 2 year option, but just call it an upgrade? It would just be an additional subscription period, but would guarantee people get the fall back license and clear up some of the confusion.
It also has the affect of making people feel like they are simply upgrading for two years as they have in the past (which they technically would be), and as they want to now. The only caveat is that you would need to make clear that at the end of two years they will lose access to the AI features.
This would seem like a win/win. This wouldn't affect the other subscription periods, but on paper, the 2 year subscription would feel more like an upgrade and guarantee the perpetual licenses for the non AI features so there's no chance that someone accidentally misses out if they accidentally cancel or some other confusion occurs.
It would, for all intents and purposes, be an upgrade for customers and a pre-paid subscription for Logos.