Yes, the temperatures I get seem well above the surrounding weather, even when you've just started the engine and you'd think they'd be lower. I suppose the main thing is that they will indicate relative change - you can see them going up as the engine warms up.
I used to think, based on what I'd read online, that the crank position sensor was all or nothing - either it was working and the engine ran or it wasn't and it wouldn't fire up at all. However, I discovered in the autumn of 2013 that I was getting a regular 'high speed crank error' code logged, and that the cylinder balance values were very large whilst I was driving - in the 20s in some cases. I fitted a new (non Britpart) crank position sensor and the error no longer appeared and the cylinder balance values were much smaller. So the good thing about having a Nanocom is that you can sometimes pick up these faults before they leave you stranded at the side of the road.