Hello and welcome to you and sweet Meeko. If you haven't already, I recommend taking a look at the Sticky Notes at the top of this forum.
The answer to your question is in your spreadsheet, where is says he's been flat for the last three
days. Emphasis mine. Many cats go lower at nights, so it's possible he's going lower at night - which you aren't catching, then bouncing during the day. Is it possible for you to get a before bed test most nights? That is at least 2-3 hours after PMPS shot time? That number can help us determine if he is going lower at night. Just looking at the existing data, it's hard to say what is happening. Though I can think of several scenarios.
I notice on your spreadsheet that you've also changed his food recently. What is the % carb of his current diet, and what was the previous % carb?
When is a flat "curve" a bounce from seeing lower-than-usual numbers and when is it the result of a too-high dose?
Not in this case. If a cat has started on a safe dose, there has been home testing to see how low the dose is getting the cat, and increases have been done in safe amounts, it's not too high a dose situation. Making significant change in amount of carbs eaten (say from dry food to wet LC) can make a difference, or addressing medical conditions, such as getting a dental, can make a difference too. Some cats just take several cycles to show how they are doing on a dose.
