This is with 2.0.1 firmware:
I have a rig with Compressor in A; Green Scream in B; and then the rest of the rig...
Compressor by itself produces a modest (noticeable, not extreme) volume boost.
Green Scream by itself produces a modest (noticeable, not extreme) volume boost.
Compressor *and* Green Scream together produces a significant volume *drop*. Needless to say, this is counter-intuitive.
Suggestions...?