Hi ejtoll,
Basically, you have three choices:
1. Recreate the formula field from scratch for each new row;
2. Copy an existing formula and edit its code; or
3. Implement a relative referencing formula that will update itself when copied to a new row.
To see how to do this and a wide range of other calculations in Word, check out my
Microsoft Word Field Maths Tutorial:
https://www.msofficeforums.com/word/...-tutorial.html
In particular, look at the item titled 'Relative Referencing In Tables'. You might also benefit from the tutorial's discussion of the quirks you might encounter when using SUM(ABOVE) and its relatives.