I wouldn't sweat it at all. Luisa at LaLana wools always insists on one way, which is generally against "the norm" because of some spirituality & tradition of it - I forgot which way as it's been a LOOOOOOONG time since I spun for her. It is not going to make that much difference in the finished plied yarn for knitting, possibly for crochet, but not for knitting. If it were a singles yarn, yes, as they always track somewhat and it would be tracking differently. It's why some singles don't work as well for crochet.
Not all experts have the definitive answer on everything - still just their own opinions :). ------------------------------------------------------------------------ Suzanne Correira, www.fireantranch.com, Georgetown, TX Fiber, Yarn, Fashions, Spinning Equipment and Tools. Fiber Workshops Taught & Workshop Venues Organized.