How to split a lump sum into a monthly payment given the month the payment should start?

Please see attached

I have a sheet for an estate agents

Column B is the month and year _mm_yy format

Column J, is the %fee
Column U is the number of months,
Column V to AG are the months

Column F is the management type, L/O means that the total payment will be received in one lump sum and does not have to be split. R/C and F/M both have a % fee taken of the total amount split across the months,

But the problem is how do i tell it when?

E.g the FY is Apr13 (_04_13) to Mar14 (_03_14)
If a property was listed as R/C on _09_13 for 12 months, 10% at total of £12000. how do i tell it to assign £1200 (10%) over the 12 months starting from _09_13.

I need a formula i can enter in columns v to ag

PS the dates have had to be _mm_yy as i want to use this as a pivot table BUT because im using data validation from another Data validation using the months.