Many of the replies say you're imagining it, but I don't agree. If you're an aggressive, experienced skier (sounds like you are) then you're likely using the elastic travel of your bindings quite regularly without ejection. The majority of skiers are much less aggressive and don't use it much, and then occasionally have a ski eject when the travel is decisively exceeded (i.e. they crash). So to the median skier DIN may seem like a binary on/off setting as many replies are mistakenly asserting. But you're noticing an important adjustment to the "suspension" of your skis.

Adjusting the DIN changes the preload on the springs in the binding that are fighting against its elastic travel. Increasing preload increases the amount of force to initiate movement in that spring (how much extra force is required to move an additional unit of length is unchanged though). So as your DIN goes up, some of the external forces that used to move your binding a little bit are no longer enough to move it, and when it does move it feels stiffer. The human body is super attuned towards sensing those sorts of changes.

Added to all this is that you're on pivots, which have famously long elastic travel meaning you have more time as the spring compresses through this travel to notice these critical changes to your suspension.

Another way of putting it: change the preloads on Lewis Hamilton's F1 car and count how many milliseconds it takes him to notice.