Putting a link to your Intro thread
http://www.felinediabetes.com/FDMB/threads/hello.186242/#post-2068640
Since you are using Vetsulin that would certainly be too low a number to give a shot. From your intro you said that Pip was diagnosed 10 months ago and started on 2 units of Vetsulin twice a day. At the curve you had done you said that dose took her far too low, so it is good that you dropped the dose.
Home testing is the best way to get a good picture on what is happening with your Pip. Good for you to have started...this is the safest way to know what you should be doing. Also your vet had suggested DM dry, which you chose not to use. Again, good for you to change to a low carb wet food.
Do you have any other glucose readings from the vet...when Pip was diagnosed, or any other tests the vet did? Kitties can often have higher glucose readings at the vet because of stress. If Pip had any sort of infection at the time of diagnosis this can also raise glucose numbers. The best thing you can do is to continue with your home testing and post for advice on whether it is safe to shoot or not. Doing a curve on Sunday will give some valuable information. Here is some good information on Vetsulin:
http://www.felinediabetes.com/FDMB/threads/beginners-guide-to-caninsulin-vetsulin.186099/