Mechanically, I can see no reason for the above recommendation. The under-lever; a sliding lifter bar located in front of the trigger guard, was retained until 1882, when it was replaced with the top lever. It seems to be a very misplaced advertisement as late as the 1930's. It may have been competitive marketing that drove the comments to avoid the top lever during the transition phase. A maker of the under lever snap action would want to discredit the top lever mechanism. It is neither stronger nor easier to operate than a top lever. The metals may not have been as strong then and quite possibly they saw some breakage during the camming action of the lever.