Many vets will combine procedures during one surgery in order to save the pet from having to be under anesthesia more than once. If your dog's teeth are very bad then they might want to do it at a different time. If it was just a regular cleaning then it would not be an issue.
I don't know what made your other vet charge so much money. It does not sound like they gave great service.
Many pets get referred to Cornell School of Veterinary medicine around here when they have some complicated problem. It has a lot of very good doctors and advanced technologies. It is very expensive but not as high as your previous vet!
