I wonder if the fees Patreon takes goes up on the smaller pledges or if it is a set amount?
It looks like they take a platform fee which is a percentage (so 10 x $1 vs 1 x $10 would be the same) but they also take a payment processing fee. These are typically around 3% + $0.30c so would be a higher proportion of smaller transactions.
I've seen other patreons that cap the number they allow (ha, imagine Lloyd ever saying "no thanks, no more contributions"? LOL) and they normally have churn / gaps opening at the end of the month. Seems to be how subscriptions are done where people sign-up for a billing month, and apparently it makes sense to join at the start otherwise you pay for a whole month and only get a few days of benefits.