SOmething else I thought of in the wee cold snowy hours this AM, ( yes, I think about YOUR cat in the middel of the night!) was -you said he noshes on carpet and fringes and things like cardboard and such, right?
Well, wondering if there are "sugars" in these items...like when ONE biscuit threw the Beauster back into sugarville for what? Like 2 or 3 weeks? Well- maybe there is an ingredient in the making of whatever he is chomping that is "irritating" the FD?
Is it possible to give him alternate "approved" items to snack upon in your absence? Like the toy dog sized Kongs filled with cat food and water and freeze for longer "play" or some small rope toys steeped in chicken broth, shake excess liquid and freeze then put on kitchen floor ( make sure it is sisal rope and not threaded rope- this toy better given when you are home to observe) or some nip filled scatter toys and such.
Make sure you are keeping the undisireable items out of reash- no paper, cardboard etc, place heavy items on carpet corners where he chews.
Do this for a week or so and see if BG's straighten out?
Another thought- this all seemed to coincide with the tile install....are there irritating chemicals? Kitties are much more sensitive than we are, smaller, process faster and He is home ALL DAY where you have a break and go to work. Just a thought.
Also- if you are concerned about "induced" FD, take him off the insulin for a week, DO THE CURVE, and re-evaluate.
I know you don't necessarily share the idea that the next cylce or two are reflective of the prior cycle or two as I believe, but it is possible that 400 something after missing shot was rebound from the shot before?
It may be a reach, but your little Jeddie is a toughie right now so looking for answers.
keep us posted.