Your home loan repayment has two parts 1) Principal 2) Interest.
Under Equated Principal Amortization, principal outstanding will reduce by an equal sum on each repayment cycle date. The reduction in principal amount will be arrived at by dividing the total loan amount by number of instalments over the period of the loan.
Under EMI based reduction, the sum of principal and interest component payable monthly on repayment cycle is equal during the entire loan tenure (assuming no excess funds are parked by you in your Super Saver account). Hence, principal component repayable monthly by you is as per the amortization schedule drawn at the beginning of the loan.
Interest component under both the limit reduction option will be calculated on the net utilized drawing power (i.e. drawing power set in the Super Saver account minus End of Day (EoD) balance of additional funds parked)
Click on the link for illustration