The relief provided for in subdivision four of this section shall not be granted unless the improvements were made after September 1, 1951, except to the extent that a recovery, allowance or credit for or on account of the value of any improvements, including improvements made prior to the effective date of this act, might be granted, in any other action or proceeding, to the person maintaining the action provided for in section 1503.
N.Y. Real Prop. Acts. Law § 1523