If I remember correctly, the knobs were only active (or the most active) at/around mid-stick because that was where hover use to be flown at (mid-stick). Today, it seems that even beginners are skipping this step and going straight to setting up hover at 75%-ish stick and setting mid-stick to 0° pitch.

If memory serves, the knobs adjusted the middle point of your pitch/power curve because this point use to be associated with the hover point on the curve. On an old 3 point curve, it adjusted the middle (hover) point (50% stick). With a 5-point curve it adjusted the 3rd point (50% stick) ... again this use to be the hover position for beginners.

So, even in "normal" flight mode, if you have the "normal" curve set so that 0° pitch is at mid-stick and you are trying to adjust the knob to affect your hover pitch (now at 75%-ish stick), then the knob will probably be disabled or have little affect until the stick is in the area of 50% stick (0° pitch). Flying with 0° pitch at 50% stick (not that there is anything wrong with this) has made the hover pitch/power knobs practically useless.

If you are flying with a curve where hover is at 50% stick, the knobs should be used to make the heli flyable enough to let you know how to adjust your curves. Once the curves are set correctly (or at least suitable), then disable the knobs. The position of knobs can be bumped or moved. Can you imagine the head-ache of relying on the knobs to be in a specific position in order to fly?

Ween yourself off of using these knobs as soon as possible.
Good Luck