I would still appreciate it if someone else could run some solo VC numbers on a training dummy to confirm my results. I understand the buffs in a group or raid and the mitigation debuffs on the mob could account for some of the discrepancy I'm seeing between solo and raid procs. However, I think there's something else going on. Perhaps it's just the mitigation debuffs and VC is getting double dinged by mitigation, once when recording on RO and then a second time when VC is being partially mitigated.
Btw, your results pretty much confirm mine; 387203 damage once every 5 minutes or 1290 dps group-wide. So VC is contributing about as much group-wide damage as Aria; 1250 or PotM; 1015.