For all retirement fund purposes, the length of service of a police officer participating in DROP shall remain as it existed on the effective date of commencement of participation in the DROP. Service thereafter shall not be recognized or used for the calculation or determination of any benefits payable by the Upper Dublin Township Police Pension Fund. The monthly average salary of the police officer for pension calculation purposes shall remain, as it existed on the effective date of commencement of participation in the DROP. Earnings, increases in earnings and length of service increments after the DROP election date or increases in earnings thereafter shall not be recognized or used for the calculation or determination of any benefits payable by the pension fund.