I have a number of accounts which were over charged interest at a rate of $22.5\%$ (most accounts, some are $21.5\%,19.5\%$).
All these accounts needed to be charged $18.5\%$. I have the total interest paid to date figures and need to reverse the overcharged amounts.
I am calculating this in Excel and am not sure if I have done it correctly.
I will use one account as an example:
Total interest charged = 1591.48 @ 22.5%. Should have been 18.5%
My formula is 1591.48*0.185/0.225
The result is 1308.55 which gives a difference of 282.93.
Could someone please tell me if this is correct. Thanks in advance