Regulation X prohibits the use
of an average charge for any settlement service if the charge for the service is based on the loan amount or property value, such as transfer taxes, interest charges, reserves or escrow, or any type
of insurance, including mortgage insurance, title insurance, or
hazard insurance, and also requires the settlement service provider to retain all documentation used to calculate the average charge for a
particular class
of transactions for at least three years after any settlement for which that average charge was used.