Middle Class Borrower Protection Act of 2023 This bill rolls back changes made by the Federal Housing Finance Agency (FHFA) to the fees charged by Fannie Mae and Freddie Mac for a conventional single-family mortgage (i.e., loan-level pricing adjustments) and restricts future fee adjustments. These changes, effective May 1, 2023, revised the fee charts that provide percentage adjustments based on a mortgagor's credit score and down payment. The bill reinstates the fee structure that was in place prior to May 1, 2023. The Government Accountability Office (GAO) must report on the changes made by the FHFA. Further adjustments to the fee structure by FHFA are prohibited until 90 days after the publication of the GAO report. After this period, FHFA must follow Administrative Procedure Act requirements when proposing adjustments to the fee structure. The bill also requires that, to the greatest extent feasible, revisions to the fee schedule must be based on risk. Further, FHFA, Fannie Mae, and Freddie Mac are prohibited from imposing any loan-level pricing adjustment fee that is based on the ratio of the debt of the mortgagor to the income of the mortgagor.