Just thinking out loud here, I’ve been obsessing with the LPF dial. It has much effect compared to the switch. The only thing I can see is that it may be a short-range low pass filter, while the switch is a broader-range, and perhaps steeper, filter.
For instance, Switch 1 might drop the filter to, say, 1KHz, walling off treble frequencies. Switch 2 might drop to, say, 300 Hz, cutting deep into the middle frequencies, hence the mid-scoop.
The LPF dial might fine-tune this LPF, allowing it to move +- a couple hundred Hz, a range which would vary along with the exponential scale of frequencies.
The Presence dial is simply a Treble, adjusting the volume of a fixed band of treble frequencies. It has much more effect on high end than the LPF dial.
Seen this way, one can see how it can make sense to turn one up and the other down.