Spreding a number wholly and equally over a fixed number of cells

Hi Guys,

I was hoping someone one can assist I'm looking to build a calculator that will split a fixed delivery quantity over 24 months to the nearest whole number and leave the remaining balance to be paid on the last month.

I have a attached an example of what I've done so far. but as an overview.

The problem is I can't get it to evenely spread over 24 months where the qty owed at the end of month 24 = 0

If someone can assist or is capable of building what I'm looking for im happy to retain services. Only if you teach me at the same time