Microsoft Excel Stimulation Problem

Dear Excel Expertise,

I've the following excel stimulation problems, which I need a solution badly.

Assumption: Assuming 2 conditions stated: Expected First Sale (Jan-15), and Project Period (3mths)
Objective: Stimulate the Average Contribution Margin as per months, depending on "Expected First Sale" and "Project Period Mth"
Question: Average Contribution Margin (kE) MUST reflect Not Only on Jan, but Feb and Mar too
Note: Expected First Sale Begin on Jan-15, Since it is a 3Months Project Period, hence the Value "16.80" should be reflect in Feb15 and Mar15 too.
Attached is the working file for you guys to work on.

Hope to hear form you guys soon!