Well, whether to downgrade a jump is more of a technical specialist issue than a judging issue. Unfortunately we don't have a trained caller to do this for us, and whichever of us might volunteer, we don't always have the camera angles or slow-motion capability to do it accurately.
But individual judges can reflect underrotations in the GOEs. Of course with falls there would be -3 GOE (and fall deduction) anyway, so there isn't an additional penalty for underrotating unless there's a caller to determine which jumps should or shouldn't be downgraded.
But when in doubt, give the skater the benefit of it.