By definition dual mono is not stereo, and when an algorithm is run in stereo it’s sounds different than in mono or dual mono. Depending on the pedal you have, 1 or 2 algorithms could technically run in dual mono. True stereo is always going to give you a different perception of space. A dual mono signal could mean your running copies of the signal from both outputs or running two independent signal lines from one algorithm. But in each case it sounds different than stereo.
