But in answer to my specific question, does changing this affect voice one bit?
Yes it does, quite a bit actually! Sometimes when it trying to hang on to a Lte enabled site it's quite bad....real bad. Now if the phone is on either a good strong Lte site, or an HSPA site, it's good really good. Actually great, and is the best phone I've had in years.
When moving you go from site to site so you won't notice, but when I'm in my recliner I want to throw it against a wall!