MRP - Credit Ceiling Review

Is anyone aware of any possible MRP adjustments that can be arrived at by reviewing the old Credit Ceiling calculations?

We have been approached by a firm suggested a review of our CFR/MRP as far back as 2004, including a review of Credit ceiling calculation.

The credit ceiling method was replaced by the regulatory method and Adjustment A in terms of Supported borrowing and we have since amended our MRP policy to move to the Annuity basis for both Supported and Unsupported borrowing.

Is it not the case that you can no longer look back at former MRP policy and arrive at historic 'overpayments' to offset some future MRP payments? My understanding is that any future MRP policy changes can only be 'from this point on'.

Really not sure where they are aiming to go with this potential review...any thoughts would be greatly appreciated.