That cop show on Victoria ch.7 say 100mm from the lowest point keep in mind the weight your putting in it like passengers tools or towing weight can further lower the car at any giving time..
South Australia work on a different system to other states, when it comes to height measurements.....
So yes what you are saying works in Vic and possibly other states, but when it is measured at the transport department, they do it from the base of the wheel arch, to the centre of the rim., in this state
And having extra weight in the car, the police aren't permitted to take the measurement, with that weight in the car and issue a defect. There was an incident a few months back, in the riverland, where coppers did that and they copped a massive rap over the knuckles, from their superiors and all defects issued were revocked