I've been parked in a caravan park for the last 7 weeks till we found and bought the new house (settlement next week) so I haven't moved much, but I can say the greywater tank put in by Mackay Jayco sits on half full when empty, even after they fixed it the first time. Mind you, the fix was actually putting in the sensors that they forgot to install. Some problems are not J-Hub related they are related to sensor orientation.
From observation on my van I can say that the installation of the sensors is pretty shocking. The readings on the screen can not match the visual on the JHub. The bottom sensor is too high and does not follow the manufacturers recommendations on any of my tanks.
The JHUB does not have a Setec (the manufacturer) recommended sensor installation. The Drifter does (same manufacturer), and it is above.
When I have time I'll take pics of my tanks and the Jayco installation so all can see what is counted as acceptable by Jayco when compared to Setec recommendations.