I often find variances in charge weights between different manuals... but usually its not too far apart.  Personally, I consider the Hornady 9th and 10th editions my loading Bibles!  I HAVE discovered errors in load data in Lyman's 49th edition... a couple of which I would consider dangerous.  I also remember hearing about a guy who's Garand went boom with deadly results, and the guy had been using Lyman's 49th.  I'm not saying his failure was due to a manual error, there was also the possibility of some Bullseye finding it's way into the case too.  The point I'm trying to make is it's always a good idea to check several sources when working up loads!