To be clear, by channel would normally be the left half A side and the right half B side of a dual-effect algorithm. You tagged DualVerb, so that is the Reverb A & Reverb B parameters. It could be a ‘balance-type Mix for Delay A & B or Pitch A & B in other algorithms.
You picked a unique one, because it can be routed a little differently. But the numbers with those letters indicate the relative levels, or strength of effect compared to its ‘sister’ effect.
The widest will alway be straight up at 12 o’clock. A10+B10. A10-B0 would be all A effect, and vice-versa.
I’ll link the pertinent DualVerb section, if you haven’t seen it.
https://cdn.eventideaudio.com/manuals/h90/1.8.5/content/algorithms/reverb.html#dualverb
I’ll also link an unrelated Delay section, because it dives into what the differences are between mono and stereo use.
https://cdn.eventideaudio.com/manuals/h90/1.8.5/content/algorithms/delay.html#digital-delay
