I agree that it's confusing, and I was originally using the total number of mediums to determine if the prefixes should be added. The thing that bothered me was multi-vinyl releases: A1, B1, C1, D1 don't ever need prefixes, and this is just painful to read: (1.A1–1.A4, 1.A6, 1.B2–1.B3, 2.C7, 2.C9–2.D1), but maybe it's just me? Anyway, I can either revert this behavior entirely or find a solution that covers both situations.