Won’t work because the source needs to match the data type.
Consider changing your data structure
Thing: Money
Fields:
Amount (number)
Type (text)
Date (date)
Debit/credit (could be yes/no, or for developer clarity can make text)
Then in your repeating group, pull ALL moneys. Do a dynamic sort and you will be able to change the source based on conditionals, filtering by type or by debit (money get) or credit (money used). Your running balance can be easily calculated with :filter for the different types, operators, date ranges. Make sure you learn the “group by” operator as well, I feel it will serve you well in this situation.