Geese mate. If someone told you to jump of a tall building with a sheet as a parachute because they saw someone do it before, would you??
Just because you got taught 1 technique (what seems a while ago) doesn't mean it is still taught as good practice.
I've personally haven't done any courses so won't weigh in on who's right or wrong.
But on a side note you should be equipped for your trip.. If you know you'll be doing 100+ meter tows then you should have enough straps to cover that distance as no, winches don't come in 100m lengths.
But also what you got taught maybe be relevant to area and terrain. That doesn't make it right australia wind.
You try your technique on a 50 degree sand hill. It won't work. So.. You either go backwards, or winch forward.