The SAAMI specs
, often copied into loading manuals, are actually for manufacturers to ensure compatibility in all brands of rifles chambered for that round. The COL, in particular, is mainly to guarantee the round will fit into and feed from all SAAMI compliant magazines. If you are playing with longer-than-standard COL's, which the Overall Gauge allows you to do, you are often going to be looking at single-loading, as the resulting cartridges can be too long for a magazine when fit to the throat, as you've discovered. That's all fine, though, as long as you develop your load exclusively for the gun you will use it in.
Please also note there is no one magic distance off the lands. Different chamber and bullet combinations have different preferred distances. This is Berger's recommended procedure
for finding the best seating depth, here.