Without having more information about your cat, I would stick with the current dose. However, we don't know if the dose dropped your kitty into low numbers and as a result, that scares pre-shot number may be a bounce into highs after a low. Vetsulin is the kind of insulin that can drop numbers hard and fast.
It would help us a great deal if you could set up a spreadsheet so we can follow your cat's progress in response to the insulin dose. There's information in the post on
helping us to help you that will provide links to setting up a spreadsheet and some of the basics we use here.