JC, OK, I understand logbook time is rotor start-stop. I got the impression the OP was talking about recording time of day for each start/stop event as opposed to elapsed time. I fly with a lot of FOs who are twitched about recording clock times merely because some logbooks have columns for this (why??) but surely there isn't a requirement to do this - is there?
Do engineers trained for ground runs claim flight time then? Or pilots doing ground track and balance runs? Bizarre!