Brian,
Through several years of experience, I have found that the availabilty percentage to the agents using VOIP is low. While using VOIP through a Soft Phone, availability was down to 83% using Cisco 5300 routers for this type of conversion. When we switch to a hard set IP phones however, this availability raised to 99.999%. 83% is way low when you are talking about inbound calls. Has your company resolved their availability issue regarding their VOIP configuration? If so, could you explain how this was accomplished?