How old is Payson?
When i went to training with Denver he did not do to good with the treats eithier he did like being called good boy though and when the other dogs where getting there treats he seemed intrested but would'nt take the one's i had I tryed alot of diffent kinds and he loved them when we wore home just in training he cared less i ended up getting
Gerber Sticks there for toddlers and they look like little hot dogs they make a few diffent flavors like chicken
beef, turkey .ect. as soon as i brought them with me he would listen to anything he just wanted the treat
So that's what worked for me
The only down side to it was when we did a command where they came ALL the dogs came to me instead of there owners

I'd give that a try and see if it works

Good Luck