I really do think Sam does understand the exercises. He will do a heel at the park with no treats if we are walking along. But if I try out in the back yard....mope, mope, mope, plod, plod, plod. Today after Mr. Boats came home he asked Sam to "Down" and had a cookie when he asked. Sam went down but grumbled as he did it. Mr. Boats looked at me with his eyes the size of dinner plates and asked me if I had heard that.
Hmmmmm....I saw that as "That's one more red flag that Sam is getting an attitude. I am going to switch to a prong collar and start to give corrections when he doesn't listen, cops an attitude, or is apathetic. Can I also correct with the same magnitude if his mind is on the dog that just walked in the door and not me?
He does know sit, down, stay, and come. He's learning "finish you dog" right now. I don't think he knows that. But you're right, if he doesn't do the exercise right, there's no real consequence other than do it again until you get it right. So, it a nut shell, I should make him know I am not pleased in the least when he blows me off or couldn't care less about doing obedience.
Just so you have a little bit more info, we don't have any issues about dominance with Sam...he waits at the door, no growling with food, bones or chews, gets off the furniture when we tell him or any of the tell tale signs of dominance I read on here.