Cumulative Billing — List & Collection

Cumulative billing keeps a rolling balance per customer on an append-only ledger — one row per customer per period, where due rolls forward by formula (previous due + this bill − paid).

Three generation modes

• Start of Month — bills all active customers on the 1st; new customers get a prorated first month.
• Billing Last Date — anniversary billing on each customer's own date (1–31).
• Custom Date — admin triggers for a chosen date.

Collection uses the green Bill Receive button: received amount, auto-VAT, payment method, receipt number, optional discount, and a Bill Up To date. Without the Set Next Billing Date checkbox, payment is recorded but the cycle does not advance.