Need Multiple Stopwatch Timers on Worksheet

I think I finally solved it. Instead of using stopwatches, which I couldn't figure how to do, I just subtracted the start time from now(). I would appreciate if someone could look at the formulas etc. to see if what I did makes any sense and if it will work for about 70 stations. Another thing that I would like to do if possible is to have the "Time on Station" always running so that I don't have to keep pressing F9 all the time to update. Any comments on how to do this better will be really appreciated.