I'm not super surprised given there's lots of juggling of levels of different voices and stages along the way. This was an issue for me with my Future Impact too and I find that the C4 is a bit more responsive and has more refined touch for the output volume in the interface and the pedal. It's not C4-specific though, this is something that I go through with other pedals too.
A couple thoughts:
If you're like me, my 'home practice/editing' environment is fairly different from my live performance environment. My stage gear is generally packed away or in our van. That rig is 6' tall and 2500w of power with a really wide frequency response that's fairly flat and accurate. At home I use a basic 112 (Avatar) and a LM2 for practice. It's not even or all the representative but it doesn't put cracks in my foundation slab either.
By nature stuff that seems balanced for volume and tone is different when I get into the live setting. So I count on 'ballparking' at home and adjusting during soundcheck'. Doing it with volume is easier than tone though. My stage rig can produce stuff above and below that my home rig can't I won't know how deep it'll go until we hit stage.
Best chances for success from my perspective:
-The C4's default setting is 'standard mode'. The very first thing I did was move to "preset mode". That way you can adjust the stuff you need (like output volume on a patch) then hold the main button to save it in the pedal. You don't need the editor to fluff with your settings and save. The light flashes when you've changed a setting so that you know it's changed from the original patch and you can decide to save or not.
-If you've got output volume problems and don't love the alt/volume situation on the C4...set one of the CTRL knobs to output volume at least until you're totally dialed in and saved. Then switch it back to whatever after you've got things fine tuned at a later date. On envelope filters my biggest tweak is the sensitivity, so I set one of the knobs to that always and I adjust it every show so it's one of my CTRLs on my envelopes.
Hey @rsmith601 one quick request...a setting for the alt function button (in the Neuro editor globals for C4) to make the alt button last longer than 6 seconds. It's just not enough time to make an adjustment then test it effectively and I found myself hitting it and re-hitting it a bunch of times to get my fine tuning on sensitivity just right.
Either an opt for a longer time or 'hit the button to get out of alt mode' would be really great.