This blog may be relevant for you if
- You regularly work with one or more service agents from the same supplier and
- You need to staff them to more than one project.
The usual approach is to create project purchase requests from within the projects which in turn leads to one PO for each and every project.
The alternative approach uses a "blanket PO".
Via this PO you order a service - in my example "Senior Consultancy" from a supplier.
You account assign this PO to a cost center.
Then, you simply staff the service agents of that supplier to several projects.
The system will then check if it finds "more specific" POs that are directly account assigned to the project in question. If not, the system will default the "blanket PO" in the time sheets of the 3rd party service agents.
The service agents will then be able to record any service in the projects they are working on.
These services will also be available for project invoicing (see e.g. time approval).
The service which is however recorded in the goods and services receipt is the service that you ordered from your supplier. Thus, you will have to pay exactly what you ordered while you are free to let the service agents render different services in the projects they work on.
You might tend to leave the POs open for quite a long time. The recommendation, however, is to close and recreate them regularly, say on a quarterly basis. The more service agents work on the POs the more often I would close and recreate the POs.