Yes, concurrent chats are reflected in the Forecast.
We incorporate chat concurrency into the Forecast by calculating the precise AHT of each Chat workstream. We are looking at a time where agents are actively engaged on a Chat and are taking into account the fact that they move between the active chats as well.
Please keep in mind that while we use the concurrency to calculate the incoming volume and the FTE you will need to handle it, we do not show how many concurrent chats each agent could handle.