I wouldn't want to try this in Access. The main problem as I see it is that control A1 holds the preliminary amount (34k) and the first balance (C1) needs to subtract the first payment (B1). After that, the relationships change as A1 is no longer needed, and the controls involved shift to
C1 - B2
C2 - B3
C3 - B4 and so on.
At best, I think it would involve a subquery setup, which is something I try to avoid.
If it were me, I'd try involving Excel somehow - either produce the report as a spreadsheet, or link the spreadsheet to the db and the report query should be able to produce an acceptable result. That's all in accordance with me not having done this sort of report in Access, but plenty of times in Excel, so I might be biased.
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.