Well, I finally got a rep today who was able to tell me: the pharmacy changed its rules in March, from allowing refills once you've used 75% of your last-filled prescription to now only allowing them at 85% utilization.
And while that doesn't sound like a big change, it is — because that means that it goes from being able to start the refill process when we have 22 days of meds left to only being able to start it with *13 days left*. Less than two weeks.