Answer:
I know this is an old post but I don't think this is a good practice, but I also don't know of any prohibition against it. HOWEVER, you are definitely falling into potential fair lending issues if this MLO does not credit all of their borrowers. How does the MLO decide which borrowers get the credit and which ones don't?
If the FI is going to allow this they need to monitor it very closely as they are primarily responsible for any fair lending implications.