An increase in resident weighted average daily attendance and in total wealth pupil units resulting from the closing in whole, or in part, of a nonpublic school, campus school or a school previously operated by the United States Military Reservation at West Point shall be determined in the following manner. The attendance of such children for the first full attendance period of the year in which they first attend the schools of the district shall be recorded separately and a resident weighted average daily attendance, and also total wealth pupil units, computed from such separate attendance records. The resident weighted average daily attendance and total wealth pupil units so computed, if either exceeds 100, shall be added to the resident weighted average daily attendance and total wealth pupil units, respectively, for the school year immediately preceding the base year. Such additional resident weighted average daily attendance and total wealth pupil units, if either is more than 100, shall, in the second school year of attendance of such additional pupils, be added to the resident weighted average daily attendance and total wealth pupil units, respectively, of the school year immediately preceding the base year.