I encountered the following problem
A money column showing 4 sdecimals, while you expect only 2.
In the application I defined a moneyfield named amount in a table OtherTable2Child
When I sum the amount which is divided by a value (1.21) in a function total_amount() of type Money on the parent table: OtherTable2.
The result of the function of type money is shown with four decimals.
To show only two decimals add moneyRoundSpecific with num_decimals=2 in the column expression
Then it shows the expected values with only 2 decimals