Well, let's see what's specific to each. 😊

Repayment in equal instalments means that the rate you pay will be the same each month and the total interest paid will be higher than with repayment in decreasing instalments.

Repayment in decreasing instalments means that the rate you pay will be higher at the beginning of the loan and will decrease more and more by the end of the repayment period. Also, the total interest you will pay will be lower than with repayment in equal instalments.

Basically, the rate is calculated by applying the interest percentage to the balance, and as the loan balance decreases - because you gradually pay off the balance - the amount of interest in the rate starts to decrease.