Allocate amounts accross a spread of months

HI
I'm hoping someone can provide me with a formula that spreads allocated hours across the allocated months as per the attached spreadsheet.
In summary, if my date range is January to October and the number allocated is 100, then I need a total of 10 to appear in each month from Jan to Oct.
But if the range is only one month, then the total would only appear in that month's data.
thanks