Hello, this situation is normal.
If it is a China Merchants Bank credit card, after the bill installment application is successful, the current bill only needs to repay the amount other than the bill installment, and the principal amount payable in the first installment (principal payable in each installment = total installment principal ÷ The number of installments) and handling fees will be reflected in the next month’s bill. The bill installment transaction is fully offset against the bill amount, and 10% is offset against the minimum repayment balance. (Business card does not have installment service)