Whoever told you Punjabis say 'haan' didn't know Punjabi, or didn't know the difference between propah Punjabi and propah Hindi. Simsimply they are confusing one and all, I tell you.
Surdie Girl : "Aaho!"
Surdie Mummy : "Child, what do you want to eat? Should I make chicken-shicken for you?"
Surdie Girl : "You betcha!"