Average Chat Concurrency - How is this Calculating?

In both the out of the box, and custom built chat concurrency dashboards don't show a chat concurrency which makes sense.

In the out of the box dashboard, I see a max concurrency of 2-4 depending on the hour, and an average chat concurrency of 0.

When recreating manually, I've been able to drill in and see that the "0" on these average concurrency queries is actually a very low decimal point (think .13 chats per hour).

So....how is the average chat concurrency being calculated? The metric definition states that it only takes into consideration agents which engaged w/ a chat during that time frame, so the minimum possible concurrency should be 1...

See below for screenshots from the pre-built dashboard on chat metrics: