the reasoning really is just peace of mind, its a five string neckthrough bass....,ive seen plenty of them get by with just a single truss and nothing else, but ive seen quite a few with some ugly action too.... im considering two 1/4"x1/8" rods, these are the same size as the top rod on my truss(the square one, the bottom appears to be a 3/8" round) so the weight factors not a problem it would be fairly close (a little lighter) to a 2 truss neck.......which may be a better option............