So, I am noticing a more pronounced feet-on-floor phenomenon by now. Tresiba dosage increased to 15 units as well. Signs that the honeymoon phase is slowly fading away. It probably will still take at least a year until it is fully gone, but a progression is noticeable.
So I researched this phenomenon. It is driven by a hormone induced insulin resistance. When you get up, cortisol levels shoot up. One of the reasons for this is to give you more fuel. In non-diabetics, what happens is that BG levels start to creep up, which is immediately answered by heightened insulin secretion from the beta cells. This two-step mechanism facilitates the uptake of the extra fuel (the extra glucose).
But in T1s, the second step is broken. Therefore, the best way to handle this is to inject as early as possible, ideally before you get up. Why? Because this mimics closest the behavior in non-diabetics. And that’s because the early presence of insulin prevents a BG rise. If you don’t inject early, you let the BG rise and rise. This however is a situation that was never supposed to happen. The body is in an abnormal state. Furthermore, since this temporary hormone induced insulin resistance has to be countered by the insulin, you need more of it if you inject later. If you inject early, the BG is still at a normal level, and you only need enough insulin to keep it there, that is, to counteract cortisol and friends. If however you inject late, and the BG already creeped up, you need insulin to counteract these other hormones and additional insulin to bring the BG down.
This explains why those who inject early have the least amount of trouble, and why those who breakfast early also don’t experience these BG rises. Furthermore, if for example you ate something that digests slowly, and you were woken up by an elevated BG alert, and bolused for it, then this may explain why the next morning you might not have a BG rise - some remaining part of the bolus was still around when cortisol etc. kicked in after you stood up. It also explains potentially bizarre BG patterns when doing a corrective bolus - insulin is both fighting the hormonal resistance and driving the glucose into the cells at the same time, leading to complicated behavior.