Accounts receivable or accounts payable aging: the open balances per customer or supplier, split into not yet due, 1-30, 31-60, 61-90 and over 90 days past due, with totals. Reads the items open now; as_of_date only decides how overdue each one counts as. Items whose source sent no due date are aged from their issue date and counted in aged_from_issue_count. Read-only.