Hi Brigitte
Welcome to Lantus Land!
I'd like to put a different spin on things ....I find there's always a lesson and something for members to learn for the next time because there will be.
Corduroys +12 was 167. Sienne said she thought you were safe to shoot....and you were. Also as she said, we encourage you to shoot above 150 and if you get a PS below 150, post for help. If you had shot the 167, you could have fed and numbers would have come up. By stalling and not feeding, the numbers continued to drop until you had to skip.
If you get a 150 or below and post for help, then a member can walk you through safely shooting and we teach you to gradually shoot lower and lower. Our commitment to you is if someone helps you shoot your lowest number, they stay with you as long as necessary until Corduroy is coming up.
Let me answer your other questions.
In a normal cycle (unless your kitty has a late nadir), the +10 and +11 should be rising numbers. If you have gotten one of those tests then you can tell if your PS is a dropping number or a second dip. Lantus is known for second dips. You can identify a second dip because there would have been a nadir, numbers come up, then at PS, numbers drop. Second dips are safe to shoot because the dip is never lower than the nadir.
Contrast that with a dropping number. A dropping number is where the BG slides down all cycle and the lowest number is the PS. Shooting forgoing numbers can allow you to take advantage of the overlap and carryover between two cycles. However, you need data to shoot lower dropping numbers (below 150). You need to know if your cat gets a food spike or not at +1. You need to know exactly how your cat responds to food management.
Lantus and Levemir are depot insulins. Their action is different and since you use Lantus, I'll explain that one. When you start giving shots, the kitty doesn't generally use the insulin of those shots off the bat. Instead, the insulin is deposited as a precipitate in the subcutaneous layers and when the depot (formally called storage shed) is full at the current dose, then the cat starts to use the Insulin that you shoot. Here is a great post on the
Insulin Depot.
The nadir can change from cycle to cycle and the depot can affect up to 6 subsequent cycles although in most cats it's usually 3-4 cycles.
One hint on how a cycle might evolve is in the +2 test. We urge you to get a +2 as many cycles as you can.
If the +2 is much higher than the PS, it's likely to be a slow cycle.
If the +2 is similar to or same as PS, you should be prepared for an active, Lantus cycllr.
If the +2 is much lower than the PS, you could expect a very active cycle.
I hope I've answered some questions.