A firm must not impose one or more charges, on a borrower under an agreement for high-cost short-term credit, that, alone or in combination with any other charge under the agreement or a connected agreement, exceed or are capable of exceeding 0.8% of the amount of credit provided under the agreement calculated per day from the date on which the borrower draws down the credit until the date on which repayment of the credit is due under the agreement, but if the date of repayment is postponed by an indulgence or waiver, the date to which it is postponed.