PAR Replenishment reorder qty is 0

Summary:

We are looking to generate Periodic Automatic Replenishment (PAR) purchase orders for expense items in non-quantity tracked PAR subinventories. Currently all the subinventory are expense type.I need to understand if i am creating a PO with 20qty for an example and i do a under receiving and trying to PAR replenishment again
Also all the PAR count method is at count and method is at Order Par
what is exactly required so i can do the PAR replenishment with one item again and again

is it because we have on hand qty ?
or how it works please let me know.