When filing your 1701Q, you may encounter this field:
You enter the amount you overpaid in your Annual ITR for the previous year in this field.
If you overpaid, then you would have a negative number (in parentheses) in your 1701:
Note that the option "To be carried over as a tax credit for next year/quarter" was selected here. The taxpayer overpaid by 6,397 (field 28).
Given that, the taxpayer will enter 6,397 in the "Excess Credits from Previous Year's 1701" field.
If it's a positive amount (not in parentheses), then it's not an overpayment. In that case, you enter ZERO since you don't have any excess credits.
Note that if this is the first time you're filing a 1701 EVER, then you simply enter a 0 (zero).