If you can do without the separate table, that would simplify the formula logic. If you need to sort the table, sorting on date is essential to make sense running balances so you would need a multi-column sort that could put the beginning balances back to the top. I also notices that the SUMIF formula used "="&[Account] The "="& is surplus to requirements
= SUMIF(Transactions[[#Headers],[Account]]:[@Account], [@Account],
……......……...Transactions[[#Headers],[DEPOSIT]]:[@DEPOSIT]) -
….SUMIF(Transactions[[#Headers],[Account]]:[@Account], [@Account],
….........……...Transactions[[#Headers],[PAYMENT]]:[@PAYMENT])
will do.