10 Pa. Code § 7.5
Except for F.H.A. and V.A. loans, a mortgage commitment when agreed to by the residential mortgage debtor shall constitute a legally binding obligation on the part of the residential mortgage lender to make a residential mortgage loan within a specified time period in the future at a rate of interest not exceeding the maximum lawful rate of interest effective as of the date of commitment offer; provided, however, that the obligation may be conditioned upon such contingencies as are customary and necessary under the particular circumstances to protect the security of the residential mortgage lender. The commitment may not include any condition for increase of the interest rate at the time of loan settlement, even though the maximum lawful rate is then higher.
10 Pa. Code § 7.5