If a person employed by the county superintendent of schools in a position requiring certification qualifications is assigned to a position under the same superintendent not requiring certification qualifications, the employee shall retain all sickness and injury, sabbatical leave, and other rights and benefits. All seniority and tenure rights accumulated by him at the time of assignment to the position not requiring certification qualifications shall be secured to him for a period of 39 months from the time of acceptance of the classified position. His return to certificated service at any time within the 39 months shall be treated as if there had not been an interruption in his certificated service.