I'm currently running 24bit 192Khz ASIO with a 128 sample buffer and to my joy/surprise there's almost no crackling of any kind, BUT I can't seem to get any of the virtual inserts working with audition. I also can't seem to get any of the virtual insert cables lower than 2304 samples without crackling occurring.
The cable latency doesn't bother me too much, but it does make me wonder if something odd is going on here. If I remember reading correctly I think if I'm truly using 128 samples at 192Khz shouldn't I really only need a minimum of 128 * 3 samples for each of the insert cables? Also when I go to access the virtual inserts in Adobe Audition the seem to default to a sample rate of 32000 Hz. And no matter what I choose (even 32000) the device can't be opened. Interestingly, if I shut down Voicemeter and just use the essence ASIO directly in audition I can actually open the card at 192000Khz with a buffer size of 16.

The card alone with a 16 buffer size

All attempts to use the virtual insert
Is my sound card lying about sample rate or something, or do the virtual inserts not support 192Khz? I've actually also tried to drop sample rate down to 96000Hz (the sample rate that works with the focusrite) but this doesn't seem to work either... Any ideas why this is happening?