Jen,
DCIN cats are different from other cats. They come from homes where they knew love and all of a sudden they are tossed away, or some like Luna have several homes and don't get good treatment.
In January of this year Luna was dx as FD. She was started on 5 units of Prozinc BID, that's 10 units each day for a starting dose. It was not until August 30th she went into the DCIN foster program because it took us that long to find a foster. For eight months she was treated without hometesting, who knows what that did to her body.
My experience with my own Kiki, she hypo'd a few times at the shelter and was not tested. Today, almost a full year later, her liver still kicks into overdrive when her numbers start to go below 150. I have finally decided no more Lantus for Kiki, she must be on Levemir because it's gentler, only by a smudge, but it is from what I've seen with my cats.
Luna is not Kiki and Lantus should be fine for her, but she may be similar in that her liver may be going into protection mode, we do not know if Luna hypo'd. When she was in her owner's care they are their owner's cat, we have no control. DCIN tries very hard to get owners onto boards like this, but Luna was not a DCIN assisted kitty so we could not force the issue.
So, the point I'm trying to make is we may have a very sensitive liver with a cat that's used to the dry and huge doses for a while. The sugar dance Luna is embarking on may take some time to figure out so just know that for today she is safe and in your good hands and we will start to see a difference soon but don't beat yourself up over not seeing immediate changes. We'll find the right dose for her.
Regarding ketones, she can get them at any number, they don't have to be high BGs to cause ketones so if you can check her urine, please do.
I hope this made some sense, I want others including yourself to understand why Luna is a little bit different. Thank you again for taking such good care of her.