What is the difference between the "balance" column and the "amount" column on the A/R Age Trial Balance Report?
The "amount" column shows the original amount of any partially paid invoice on the report. The "balance" column shows the amount owing for each invoice. The "amount" column is there for information purposes, to identify partially paid invoices.
The grand total for the amount column really has no meaning - it will likely be removed from the report in a future release. The true A/R number is the balance column.