I have a Moog EP2 expression pedal. It works when plugged into the YC, but the ranges I get when turning the attenuator knob are odd:

- knob @ minimum (7 o'clock): ~10% heel, ~50% toe
- knob @ maximum (5 o'clock): ~10% heel, 100% toe
- any other position: 0% heel, toe increases from ~50 to 100 as the knob turns.
(10% and 50% are approximate values, based on what I hear. I don't know how to measure the exact settings the pedal is producing)

So the only attenuator position to achieve 100% at the toe and not zero at the heel is the maximum 5 o'clock, which gives me the nearly full dynamic sweep range.

I know next to nothing about wiring, but I know that TRS connectors in expression pedals can have different wiring schemes, which might be the reason here.
I found a link with the Moog EP2 wiring: http://www.teaser.fr/~amajorel/ep2/ . It does say there that the Yamaha wirings are different.

If I were to have the wiring on the pedal changed, how would the pedal settings behave then?