When the governing body or bodies of the municipality or municipalities have imposed a condition upon such transfer that said funds shall be credited on account of the amount of the school tax due or to become due in such municipality or municipalities in any year, the board shall give credit accordingly and the moneys so transferred shall be used as and when the moneys credited on said school tax could have been used and the secretary in certifying the amount to be raised by local tax for school purposes shall reduce the amount or amounts to be raised in such municipality or municipalities accordingly.
N.J.S. § 18A:22-46