7 years later, I play for the first time and encounter the same issue. Missions 4 and 5 have my ADF needling pointing in the wrong direction, or at least out by some amount.
Heading home, I've double checked 477 mhz and do find a strong signal there, but it wants to take me to an airfield miles to the west. After reading through all these posts, I still don't see a solution apart from use the map and locate the marked location (easier for home base, less for other), or try other frequencies. I didn't find any close frequencies like the 350 vs 353, which was my first instinct to check.
Radio compass is also calibrated, though I'm not sure if that changes ADF needle direction or just the compass rose.