Approval management and routing

When setting up approvals in NetSuite, it seems that the only choice is to select Supervisor in HR tab of employee record and this disables the Approver field. You need to leave the Supervisor blank in order to use the Approver field.

We need both (as I think most companies would). Typically there are two stages of approval, especially for purchase requests and expense reports:

1. Employee creating expense report/purchase request has a certain limit that does not require approval in order to submit, or a employee other than their supervisor is responsible for processing and approving up to a certain limit.