Rhonda, the fact that you're getting into blues means you might not need to be increasing.
With Lantus, you should hold the starting dose (which should be based on how much your cat weighs) for at least 5-7 days, get at least 4 tests in per day and then re-evaluate the dose. Lantus dosing is based on how low it takes them, not the Pre-shot number, which it sounds like your vet is basing it on.
It's important to always get a Pre-shot test to make sure they're high enough to give insulin at all....and then a test somewhere between +5 and +7 on the AM cycle and at least a "before bed" test at night to make sure they are going to be safe through the night. Most cats go lower at night
Come on over to the Lantus Forum.....there's lots of experienced eyes to help you learn everything you need to know about keeping Shiloh safe as well as getting the best regulation possible!