I listened to a lecture by Dr. Pat McCormick ( scheduler for NCAA officials, and also a top NCAA official himself ) this past fall during the KWOA clinic. He made mention a few times about how officials should not "coach" specific participants during a match. He also said that it is important for officials to address both wrestlers with comments made. I younger kids matches at the kids level. In will certainly tell one wrestler or the other to improve their position.
By the time I get to the 12 year olds and older I don't use such comments unless im addressing both men. The only reason I do this with some of the younger kids is because they may not realize that they are in a stalling situation (usually because some of their coaches are screaming "cover the hips", and they never try to run a pinning move ). There are times to address wrestlers and there are times not to.