If you hit your head in the middle, it's too low. I've seen 7' ceilings that angle down to 3' knee walls to no knee walls. However, I've seen these low areas effectively utilized in the overall use of space. So, in the absence of governing zoning regulations and building regulations (unregulated areas), look at it from how it is being used and comment accordingly. You may use the entire floor space then adjust for functionality.
You are correct. That is an ANSI standard. However, as we all know, there are some busy bodies at work in every regulatory office that think they understand better what a room should look like. Just check with local authoroties to see if they have changed it.