Formula to Spread Costs Between Months and Years

Hello,
I have an issue I think I may be looking at incorrectly and can't seem to find a simple solution. See attached. (I added in some arrows for the first month so it is easier to follow the logic)

I am working with monthly revenues. Revenues are earned in a specific month but only a % is received in that month and over the next 4 months. I need a formula that will spread these revenues earned in 1 month over the next 4 months.

Currently, I have a complex Index/Match formula which works until September. September, October, November, and December do not work correctly because once the months roll over from month 12 (December) back down to month 1 (January), my formula cannot recognize the range.

Essentially, I need the formula to return the correct amount that is being paid, even across different years.

I don't know if my formula can be modified or a new formula would be more efficient. Any feedback would be helpful. Thank you

(This post originated from Commercial Services, which I just requested be removed from that forum)