Filling Empty Cells With Value VBA in ever changing file

I am trying to make a program that will run on an exiting spreadsheet generated by someone else. This sheet will change in number of items size every time its generated but I know that the first 5 rows will be constant throughout. I have figured out a way of doing the process by hand operations in excel but I haven't been able to produce any vba code that could do this automatically.

The attached sample file file shows a starting point for the file, the end result and the excel calculations needed to get there.