As long as first round was given and your kittys are going to be inorder only, I would follow advise of your vet. You've gotten 2 separate opinons from vets and both concur with one another. So much has changed in vet medicine it's amazing. Personally, we just changed from a vet who we adored (he is 70+) to a more younger (30 yr old) vet in 2 man practice. Skinny had allot of tummy problems and this younger vet figured it out.

Good Luck