Financial Statements- Finance Lease

furno11

Hi,

I am taking my Financial Statements exam next Tuesday and am just trying to fill up the cracks in my knowledge!

Could someone please explain the sum of digits method regarding a finance lease?

I understand the method if you pay at the end of the year i.e 31 December but get confused as to why the formula changes if the first payment is on the 1st January?

Any info would be much appreciated.

Thanks,