It looks like all you need is a table. Formulas in tables will automatically fill down when you add new rows to the table, so there is no need to keep formulas outside the table as you have in your example.
You can see how to convert an ordinary range of cells into a table in the video lesson: Expert Skills Lesson 1-11 Convert a range into a table and add a total row.
I have attached a copy of your workbook with the table applied:
I hope this is the answer you were looking for, but please feel free to reply if you need any more help with this.
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