How to sum three times in a single getdatacell

You can write a loop that will run as many times as you want. Dim a result, set it to zero. First time through the loop, grab the amount from Time1 and add it to the result. Second time through the loop, grab the amount from Time2 and add it to the result. Third time, same. Exit loop and you have your result.

Be careful that you write an exit to the loop as you don't want it loop indefinitely.