Where can I add the deduction showing in box 74 and 75. It reduces box 20 but it still should be allowable deduction

Box 20 includes RPP contributions for current and past service the amounts in Box 74 and 75. Once these boxes are entered it reduces Box 20 but it looks like the deduction for box 74 and 75 is not showing as a deduction anywhere and it is an allowable deduction