On 3/16/2019 I wrote a check for $173.72 knowing I still needed to figure out where the $60 came from, and not knowing this bill that would arrive three days later would show I had another mysterious credit for $30 applied to open balances, meaning I only owed $143.72... (see how confusing this is getting?!?)

Only one new Date of Service was added to this bill as compared to the prior month. See 2/27/2019 DOS on the second page and the EOB was not back from it yet, so it was not adjusted....

BUT... as alluded to earlier, somehow, without me making any payments, more patient payments are showing up?!!?

Another $30 payment was applied to the 12/20 DOS and a $15 payment was applied to the 2/27/2019 DOS that has not been fully adjusted yet??

I don't get it... who is making payments on my bill...

The EOB is not back for the 2/27 DOS yet. We can tell that because no adjustments are made. Putting the 301 balance in the balance column is confusing but fairly standard billing practice. It's there, but it does not get included in the "due from patient" box (although you'd have to know how this all works to get that).