Did you get any tests last night? Wondering if there is a bouncy explanation for the rise to black tonight.
Dyson has got to the size of dose where you should think about asking your vet to test him for secondary endocrine conditions that can cause the need for higher doses. The conditions, acromegaly and IAA (insulin auto antibodies) cause insulin resistance. Acromegaly is caused by a benign pituitary tumour that causes excess growth hormone to be output - which in turn causes the diabetes. The latest research (2015) shows that about 1 in four diabetic cats has it, not all with higher doses. IAA can either go with acromegaly, like it did with my cat, or be on it's own. Think of it like the cat's body fighting the injected insulin like an allergy. It's a condition that can go away on it's own after time. There are treatments for acromegaly too.
There is a third condition called Cushings that can mean a cat needs a higher dose, but it's less common. The tests for the first two are blood tests where the blood is sent to Michigan State University and can be done at the same time.