i think you're thinking like i was about the insulin - it's like a mathematical equation. Take 1 cat, add so many units of insulin = a healthy cat. what i've learned is that insulin is a hormone - think 13 year old girl, sunny one moment and doors slamming the next. the cat's body doesn't always respond the same way to the same dose, so even though the dose might've been right at one point when you did a curve, over time you will see a whole different set of numbers with the exact same dose.
it's interesting to me from an intellectual standpoint, but when you realize the implications it has for your cat's body - it's stunningly clear that if you're going to use Lantus and keep your cat safe, you absolutely must test more frequently. no cat likes it, no human wants to do it, but we all get used to doing what has to be done. my cat, who i had to drag from under chairs and burrito in a beach towel for the first 2 weeks of testing, is right now sitting in the testing spot waiting to be tested so he can eat. food is a great motivator in a cat!
Click on Sienne's cat Gabby's spreadsheet - she's one of our zoomer kitties. Marjorie's gracie is another one. These cats might be, as Sienne mentioned, over 300 preshot and go plummeting down to hypoglycemic (under 50) by the nadir, then rise right back up and do it again. The trouble is if a cat goes hypo and you don't know it, the consequences are severe for the kitter - from brain damage to death. i'm not trying to scare you, but you have to understand the implications of using insulin. None of us wants ernest to be harmed and too often vets direct people to use lantus without the owner really understanding how critical it is to test your cat. lantus is such a gentle acting insulin that often a cat won't even show the signs of hypoglycemia until it's very severe.
Just take it as a " *whew* i've learned in time" experience! I don't want to make you feel badly or anything, but just want to make sure you know the implications of what you're doing and understand the importance of testing - especially those mid-cycle tests. they are critical to learn for appropriate dosage changes for ernest.