unallocated sales order is out of Credit management

Dear gurus

On credit management, if inventory is NOT allocated to sales order

(Ex. No inventory at storage location),

warning or error message show up even if the credit amount is

exceeded the limitation.

After created sales order without inventory allocation, then inventory

is allocated later, and error message show up

as delivery, because the credit amount is exceeded the limiation.

What is the concept of SAP behind this logic?

Why SAP doesn't count unallocated sales order to credit management?

Y.Kaneko