Patreon seems to have handled it worse than I thought. The Benefits Tracker tells me every tier anyone subbed to- however, Patreon apparently handles an increase in tier as an "upgrade", charging you the difference between them. As an example, one Patreon subscribed to Sketch, then Ink, then Color as each tier opened up. Across three payments, Patreon charged them in total 85$- but the Benefits tracker counts that as having purchased a Sketch+Ink+Color (40$+70$+120$).
Patreon collects payments over a 3-day period so I'll wait one more day to see if the problem resolves further, but at the moment it seems I'm going to have to go over everyones charges with a fine-toothed comb to see how much I was actually paid vs what the system says everyone is owed.