I think she’s going to need that increase to 6.5 units. She’s had time to break any bounce from the blues and the lowest you have seen on this dose is mid yellows.
By the way, this kind of behaviour, seeing nicer numbers then not again, is quite typical for a “high dose”:condition. I don’t like that name because we have seen cats on much lower doses with acromegaly, IAA or Cushings. Regardless, increasing to catch up to insulin resistance, whatever is causing it, is typical. I used to call it the dose going stale.