The fact that new versions of the software come to the consumer space first is standard operating procedure for avast, this is unlikely to change. Among other reasons for this, we believe that the business space has higher demands on the product, and the release of new versions to the consumer space first provides the needed feedback for making sure that the product is ready for the business space. There is no "lag", it is completely intentional.
We understand that everyone is eager to get out of 8.0 and that new hardware is often forced to come with Win 8, even if this is not always what the companies would prefer. While this compatibility is definitely a very annoying issue, it is important to keep perspective. The amount of our business customers that are on Win 8 and therefore affected by this is in the single % digits of the total as most (and especially larger) businesses are more conservative with their OS choices. However this does not mean that these users are not important to us and we are aware that this will become more of an issue as time goes on, for new business especially (as in your case), which is why we are actually rolling out the update to the business products much ahead of when it was originally scheduled for.
I absolutely agree with your approach to the BETA, we definitely do not recommend wide deployment on customer systems or production environments. It is unfortunate that you cannot participate in the process, but I understand that not everyone has the resources to do so. Keep in mind that resources being limited is a fact of life for us at avast also, we do our best to roll out the updates when they are needed, however even once it is started, the process takes time and resources. It is in situations like these when we need our partners, our resellers, the most. To help us explain the situation to the customer and reduce as much as possible the business lost until the needed updates are ready.
So, please hang in there and help us hold the line while we work on the needed testing and fixes to ensure this update is clean and adds to the value of the product beyond just adding Win 8.1 compatibility.