Professional and service personnel employed by a multicounty vocational center shall establish seniority on the basis of the length of time the employee has been employed by the multicounty vocational center, except that any professional or service personnel whose employment with the multicounty vocational center was immediately preceded by employment with one of the county boards participating in the operation of the center or whose employment contract was with one of the county boards participating in the operation of the center (1) shall retain any seniority accrued during employment by said county board; (2) shall accrue seniority as a regular employee with said county board during employment with the center; (3) shall attain continuing contract status with both the county and the center if the sum of the years employed by the county and the center equals the statutory number required for continuing contract status; and (4) shall retain and continue to accrue county and center seniority in the event of reemployment by said participating county as a result of direct transfer from the center or recall from the preferred list.

Reductions in work force in the center or employment by the center or county board shall be made in accordance with the provisions of sections seven-a and eight-b of this article: Provided, That only years of employment within the multicounty vocational center shall be considered for purposes of reduction in force within the center.

The seniority conferred herein shall apply retroactively to all affected professional and service personnel, but the rights incidental thereto shall commence as of the effective date of this section.