ATP for STO from Allocation vs ATP for STO from ME21N

Hi All,

We have set automatic creation of delivery for PO.

We have recently notice a weird problem. When we create STO from allocation table, ATP runs, no delivery is created when there is no stock. I can accept this if there is no stock, no committed qty can be calculated hence no delivery. However, for the same article with no stock, when we created it using ME21N...the same ATP runs and we get a committed qty/date and a delivery.

What is also not happening is with ME21N, if only a partial delivery can be satisfied, it will be split into 2 and 2 delivery. But from Allocation..totally nothing.

Has anyone face this problem before care to share some ideas as to what I should look into?

Thanks!

Cheers,

cady