I would think it could take longer on larger doses, not smaller. This is all speculation on my part but if you are increasing the dose by 0.25u, it would take longer to get the depot to fill than 0.1u. It may also be a matter of what the relative percent of the dose the increase is.
Thanks, Sienne! I figured it went something like this: cat "uses" what insulin needed from the shot, and "excess" goes to the depot. As cat "uses" less insulin each time, depot fills faster. Since Chuck is likely "using" all the insulin he's getting, based on the bounces he's been having, I figured the depot wasn't filling at all...
Thought I'd try to catch him a bit earlier than a +3... He just jumped up with me, perched on my shoulder and started purring, so I guess he forgives me for the poke a few minutes ago.
If there's research about the pharmacology of the depot, I've not found it. I honestly don't know if it's a matter of what is or isn't used. My conceptual model is that the depot is more of a steady state and when dose changes, that filled tank is disrupted. The level needs to be restored and have a chance for all of the "ripples" to settle down.