You’ve got a lot on your plate as a retirement plan provider and the last thing you need is more headaches. So don’t add to your workload and headaches by deciding to bill for the work of another provider.
I’m an ERISA attorney and if I refer a plan sponsor to a third-party administrator (TPA), I’m not going to bill for that TPA’s work. Your job is to provide the best service for your client, your job isn’t to be the billing office of another provider. Forget about the accounting aspects of it, what if the other provider doesn’t provide the work promised? Are you know going to have to refund money that was never yours, to begin with?
The road to hell is paved with good intentions and nothing good could come by doing another provider a solid by acting as their billing office.