It seems to have worked well in both directions.
Quite pleased with it as I was able to have it and Google Maps running at the same time.
Craig,
It appears to store points for transmission when it is next in range. On the way up both the Tom Tom and Google Maps on the phone took us off the Bruce Highway because of an hours delay. They both took us up through Woolooga and Biggenden. (Actually 7 km shorter) but there was no mobile phone coverage most of that road, but as you can see there are a couple of data points along that part of the route.
Next time I'm going to try running Here Maps and Bubbler at the same time.