Last time I flew there we got held up by a jet or two but Sunrise credited me with the time wasted so I didn't pay while the Hobbs was running on the ground.
Maybe you do need to ask though. I suggested shutting down while we wait to taxi back and the instructor said he would only charge for the reading on the Hobbs up to that point.
Worth checking though whether WW charge for brakes off to on, Tach time or Hobbs as this can make quite a difference.
ZA