Formula must not use the same row every time

I did take all my formulas out of my google sheet, and add this to my block =SUM(C44-C45), but how can I change so when I add new data it does not use the same row c44-c45)

I did get to a point that it nearly work, but it adds them together and not subtrack them from each other.
=SUM(INDIRECT(“C”&ROW()+1&“:C”&ROW()-1))
Screenshot_85

Hello @hendrikbez

You could do the calculation on the app and send the correct number of row to the table using the join block. Could you please see the screenshot?

Thank you