Yeah Yorkies are smart! Loki did what Logan did too. I was sick of chasing him so I just taught him "crate" and now I can say it from anywhere in the house he will BOLT to his crate and sit and wait for his treat there. You do have to outsmart them and it's not easy!
Smiggy it sounds like you have a smart one. My Loki is super smart. Sammy is slow but sweet and generally well behaved so it's OK that she took months to learn sit. Loki knows hundreds of words and even sentences. It's good to focus that
We did tons of classes.