How to show a cost per unit with DAX?

I have 5 tables, Date, Sizes, Production, Expenses & Operations. The last 3 are fact and the rest are dimensions to generate report like below.

I have a chart currently showing my daily production vs the budgeted. What I now want to create is a chart that allocates the total expense for the day over the unit of those that are produced that day. We currently produce 3 sizes battens of the same length. I tried using:

=CALCULATE(SUM(Expenses[Payment])/SUMX(ALL(Production),SUM(Production[Total]))*SUM(Production[Total]))

But this is not giving me the correct report. The report that I want would be formatted as Sizes used as filters with Date as categories and said measure as value. However, I do not know how to correctly calculate the cost per unit belonging to the size produced during the day.

P.S. Crosspost from Excel forum as I was asked to post this question here.