I use two MFII's as inserts on my mixing console.
The setup is pretty easy: Each channel of the console has an insert so I run all signals through multifaces with a lot of VST PlugIns like dynamic processing, guitar emulators, gates, reverbs and stuff.

After some time I discovered a problem. Buffer noise is stacking in the main mix. It is on pretty low levels initially since I use 128 and 256 buffer sizes but when all 16 tracks are mixed down together the noize becomes loud enough to hear in my studio headphones. I tried phase-inverting the signal on the console but phase inverters are just before the insert point on my Soundcraft BG2R-16 console.

I think developers could implement a phase-invertor on every output channel in Multifaces at point AFTER the output so mixing several outputs of Multiface wont' make so much noise.

Sorry. Bad English.