Thank you for all of your support and time with this issue. We are kind of stuck with the calendar/fiscal year model. Luckily, we just have a few weeks until the new fiscal year starts, so not a big deal. We'll enable the ARB for users once the renewal date is within the 1 year window and revisit the "early renewal" issue again next spring if anything has changed.
BTW, thank you for the recommendation of Stripe in other threads, it has been a welcome change for us.