(a) A person who is employed at least half-time in the plan during the same period that the person is employed at least half-time in a position in the teachers' retirement plan under AS 14.25.009 - 14.25.220 shall receive credited service under each plan for half-time employment. However, the amount of credited service a person receives under the plan during a school year may not exceed the amount necessary, when added to the amount of credited service earned during the school year under the teachers' retirement plan, to equal one year of credited service.

(b) A person who was employed at least half-time in a position in the teachers' retirement plan under AS 14.25.009 - 14.25.220 in the same period that the person was employed at least half-time in a position in this plan may claim credited service in both plans for employment before May 31, 1989. To obtain this credited service, the person shall claim the service and verify the period of half-time employment. When eligibility for half-time service credit has been established, an indebtedness shall be determined to the retirement plan in which the person did not participate. The amount of the indebtedness is the full actuarial cost of providing benefits for the credited service claimed. Interest as prescribed by regulation accrues on that indebtedness beginning on the later of July 1, 1989, or the date on which the member is first eligible to claim the service. Any outstanding indebtedness existing at the time the person retires will require an actuarial adjustment to the benefits payable based on that service.