Allocating a number (cost or revenue) across a quarter on calendar

Hi All
Does anyone have an elegant solution for handling a simple allocation? The solution I have involves using specific dates and it's cumbersome because I don't want to list a 'date' for each new revenue.

I've attached a screenshot of what I am trying to do.

In the screenshot, I want to list a whole number in row9, between C and N. This is how many new revenue steams were added in a particular month.

I then want the calculation to occur in row19. This formula should apply the revenue (fixed number in D4) across the number of months (fixed number in E4). If my values for D4=5000 and E4=3, the 5000 revenue should hit for 3 consecutive months (15000 total).

If two revenue steams overlap, they should be added. The revenue for a particular month in row9 should not occur for any months past E4. For example, revenue added in August should only allocate for August, September, and October.

Seems simple to do on a napkin, but I cannot for the life of me think of a formula to handle it without making the spreadsheet much more complicated.

Help for be very appreciated.

images are not helpful
please post the workbook to avoid having to recreate
please provide before and after sheets, explaining how final sheet arrived at

I will try and grab a worksheet tonight to show you here, but there is no formulas in the cells for the screenshot I posted. The screenshot is of where I'm trying to go, not where I'm coming from.

I was previously using this guide
http://www.excel-university.com/exce...nthly-columns/

With the method above, each revenue stream must be given a starting date in a MM/YYYY kind of format. It's very cluttered.

I'm trying to create a formula which takes input on the yellow shaded grid (screenshot) and allocates the revenue across a fixed numbers of months under it (unshaded grid).

Formula for E19 that you can copy across is
=$D4*(C9+D9+E9)
Adjust for Jan & Feb