Hi there, I wanted to suggest a few things. You don't have a particular method identified, and I'm not sure if anyone has pointed you to those stickies, ...
http://www.felinediabetes.com/FDMB/...-low-go-slow-slgs-tight-regulation-tr.210110/
but depending on which you may choose to follow, it will affect the suggestions people make. If I see correctly, from your signature, if you are occasionally feeding dry, you will need to follow SLGS.
Sometimes it helps when you get a low preshot to stall, don't feed, and retest in 20minutes. Then you can see if kitty is on their way back up, and based on that number you can decide whether to dose. With SLGS you wouldn't shoot anything under 90. You have had a lot of no shots. Yes, there is bouncing, but as an example, on April 27th you got a preshot of 67, no shot, but then gave him 4.5u at pm, when you should have reduced his dose to 3.75u. 4.5u is too much insulin, we dose based on how low the dose takes the kitty, not the preshot numbers. And the changing up doses isn't helping. Yesterday am, NS due to 67 (which would deserve a reduction), but you shot a 4.5 the night before, then that evening 4u then this morning 4.5u. If it were me, I would skip tonight, I don't see anything as history of diabetic ketoacidosis, which may affect suggestions to skip or not. I would try and see if you can get some consistent cycles, over the next 3-5 days maybe try 3.5u or 3.75u and see how that works. We also suggest dosing adjustment in 0.25u increase or decrease, can you do that with the insulin needles you use? You'd be surprised how much 0.25u of insulin can make. I hope I haven't overwhelmed you, I just saw you needed some help, wanted to try and offer some food for thought.
Keep asking questions, people here really do want to try and help where we can