PO distributions and Contingent worker affectations

Hello,

Looking for the best way to handle this case.

We have to bill the reel hours made by a contractor an the reel cost center (distribution) were he worked.

Steps:

Creating a Contractor requisition with iProcurement and associate a PO to it. The PO is created and budgeted for a department and the main cost center of that department (DISTRIBUTION)

Creating a contingent worker (CWK) and the assignment to the PO via Services Procurement.

Actually, we are trying to use OTL to enter the reel hours done by the contracter (CWK) via Purchasing layout. However, the CWK had worked for many cost cemters for the department.