Did this ever get solved?
No, I'm still seeing this 0-2 frame variance in my setup, even in the latest builds of madVR using the DX11 path.
The good news is that a 1-2 frame variance should not be something you notice, as long as it is never early, the bad news is that it still makes setting up the delays for multiple zones a real pain any time I make a change to my DSP configuration. (each DSP adds some amount of latency)
Right now I'm having to make six adjustments any time there's a change, and each takes about five minutes of seeking and writing down the delays to figure out the max/min variance to figure out what the delay should be that will be as close to being in sync without allowing the audio to be early.
And there are still no controls for separate windowed/full-screen delays, so you just have to pick one.