Flightplan and VOR radial disagreement

Hi all,

I've noticed a slightly annoying trend regarding VOR navigation in the sim and I'm wondering if I'm misunderstanding something...

It seems that the bearings given in the flight plan to/from a VOR are out by a couple of degrees when I cross-reference them with the purple track overlayed on the G1000 (and presumably other FMC systems). The effect of this is:

1. When I fly strictly according to the VOR radials, my flightpath tends to diverge from the purple line,

2. On the last leg of the flight, when flying away from a VOR and to the destination airport, my (VOR based) flightpath often misses the distination airport by a some distance.

Is there some dissonance between true/magnetic north in the flightplan/FMC that I'm not aware of? I'd love for someone to educate me...