I'll look to find out about the instalment amount but my...

I'll look to find out about the instalment amount but my understanding is as follows:
Under the previous method as an example say a $300 monthly repayment consisted of $200 principal and $100 interest. The payment was not received so a $25 late fee was charged. The customer was chased up and made the payment 2 weeks later. Of the $300 cash received, $25 was recognised as payment of the late fee (i.e. revenue), $100 recognised as interest payment but only $175 was recognised as a repayment of principal (200-25).
Under the new treatment, when the $300 is received $x dollars (less than $25) is recognised as payment of the late fee, $100 as interest and 200-x as repayment of principal. The remainder of the late fee (25-x) is added to the outstanding balance and is recognised as revenue in later periods. It therefore defers the recognition of the $25 late fee as revenue earned. This deferral (decrease in revenue for period 1) drops to the profit line.