This tragic accident produced 6 victims already; please don't 'create' any more victims. I am certain NAS 2b or c has nothing to do with this accident.
As compressor stall pointed out you can't manually load the GPSNPA waypoints and in fact their location is not published. One thing bothers me with these 3.83 degrees off track. The GPS does not work in degrees; it works in distance off track. In other words parallelling track. If indeed they were 3.83 degrees off, that suggests to me that they were navigating by conventional navaids. I am only speculating and I hope it's not so. Perhaps if the HSI was selected to a VOR instead of the GPS????
When I first had my Garmin 155 it had a feature that when you selected an ILS on Nav 1 the HSI would automatically select the Nav mode. After a while an AD came out and this automatic selection had to be disabled. I got caught flying 1 ILS thinking the HSI displayed ILS information when in fact I had forgotten to switch it from GPS to ILS. The same thing could happen in reverse. There is also a problem with their distances. They crashed south of the southern initial approach fix. The minimum altitude there is 5000'. They crashed at 1500'. They could have had some problem that distracted them and resulted in being 3500' too low. Or they could have thought they were much closer to Benalla than they really were.
I hope the ATSB finds the real causes so that all of us can learn.