The following information pertains to Hopson Co.'s pension plan: Actuarial estimate of projected benefit obligation at 1/1/15 Pension plan assets at 1/1/11 Other Comprehensive Income-Gain/Loss at 1/1/15 (credit) Average remaining service life of active employees in years $ 800,000 $ 700,000 $ 120,000 10 In the calculation of pension expense, the amortization related to the corridor has the following effect on pension expense: $0 and no change to pension expense. increases pension expense $4,000. decreases pension expense $4,000. O increases pension expense $5,000.