Inconsistent values with other websites

[STRAND-C]

When testing on the Money Supermarket website here -
https://www.moneysupermarket.com/loans/calculator/ I am getting different 'Monthly repayment', 'Total amount payable' and 'Interest payable' values compared to using this script on my own website.

For a loan of £7,500 over an interest rate of 7% and monthly repayment of 36 months the monthly payment across the above website was £230.84 and the total cost of credit is £810.24, whereas on my website they are showing as a monthly payment of £231.58 and total cost of credit as £836.82.

Is there a recent update to this script? Thanks