Sorry, but a vet charging to compare meters and demanding that you come into the office for visits that are NOT needed? Change vets now.
I am not sure if anyone gave you the link to Dr. Lisa's site.... good info, very good, with much on diet and in particular that myth about the dry being good for the teeth. Nope, it's not.
Feeding Your Cat: Know The Basics of Feline Nutrition
Here's a bit from the site:
Dental Disease: Long-standing claims that cats have less dental disease when they are fed dry food versus canned food are grossly overrated, inaccurate, and are not supported by recent studies. This frequently stated (among veterinarians and lay people) myth continues to harm cats by perpetuating the idea that their food bowls need to be filled up with an unhealthy diet in order to keep their teeth clean.
The idea that dry food promotes dental health makes about as much sense as the idea that crunchy cookies would promote dental health in a human.
First, dry food is hard, but brittle, and merely shatters with little to no abrasive effect on the teeth. Second, a cat's jaws and teeth are designed for shearing and tearing meat - not biting down on dry kibble. Third, many cats swallow the majority of their dry food whole.
In general, most dry food have higher carbs so if you want to get rid of the need for insulin and testing and all the associated medical costs, a cheaper and healthier option is to feed wet low carb foods.
If you think about it, you feed dry food, the BG goes up, you give insulin to balance if off and bring numbers down. Then you feed more dry and then the BG goes up, and ..... you get the picture.
I know that some people make claims that some dry are low carb but that's not the only thing wrong with feeding dry food.
I would say that if you have a cat that eats some wet, then you are good to go with removing the dry.