Not every balance should be left open-ended. A Payment Plan takes the amount left after a deposit and schedules it into a fixed series of instalments with their own due dates, instead of one lump sum whenever.
It’s set per product, so a $2,000 item can ask for three even instalments over three months while the rest of the catalog stays on a simple deposit-then-balance flow.
A Payment Plan and Flexible Payments are mutually exclusive on the same product — a plan already schedules the balance, which is the opposite of paying any amount whenever.