I can understand, and relate to, much of what you are experiencing Matt @Matt1 , but I’ve come to the conclusion that the problem isn’t [except for very rare “spoiled” instances] the insulin, but rather my body. Your insulin, Humalog, is manufactured at a very high standard, and a vial [or from vial to vial] should not develop “different strengths” between the hours of 8 AM and 12 Noon. I’ve reached the conclusion, at least for MY BODY, that wide variations in “apparent onset” and “action Duration” of insulin is because of me, and not the product.
Have you considered changing the length of your needle? I expect that you observe the “rotate site” rule, and, at least on my body, the thickness of dermas varies. Just a thought.