I have approximately the same problem.. upgraded from an explorist 200 to Legend Cx.. love the color screen & the autoroute...
Went out caching with a friend that also has an explorist 200, everything was measuring the same until we were about 50-75 ft from ground zero of coordinates... I ended up about 30 ft from where he did...
Next cache, same thing....
On the 3rd cache I fired up my explorist 200, and followed my Legend Cx to where it said ground zero was, once again my buddy wound up going a little different route i did (following his gps unit)... when i hit where the Legend said i should be I looked at my Explorist & it said I was 33 ft away from ground zero,....
went over to where my buddy was standing and my explorist said i was 5 ft away from zero, and my Legend said I was 43 ft away.... oh and the cache was about 2ft from where we were standing by using the Explorist...
I would use the Legend to tell me how to get to the cache area, and then use the explorist to find the cache, but then i am back to inputting coordinates by hand......