No. The SOPL’s are always prepared at the ends of years.
They take a loan now – at the start of the first year. So the interest in the first year is 10,000 (plus the overdraft interest). At the end of the year they repay 25,000, so they start the second year owing 75,000. So the interest in the second year is 6,750 (plus the overdraft interest). And so on….