In general, changes to loan originator comp are usually allowable when it is in the borrower's best interests. You must complete a borrower's best interests worksheet or other documentation for the individual file. That's in Section 2-71 Compensation and Anti-Steering of the 2-0 Compliance Module (and 3-0 Loan Origination Module).
Otherwise, Loan Originator comp should remain static and cannot be systematically reduced to allow the LO to have pricing discretion. The problem is not that switching from one to another systematically reduces compensation in the borrower's best interests; it could be used to raise compensation systematically.