Will Demand History Aggregate to All Other for non-Key Customer in Demand Management Cloud?

Summary

If Key Customer option is implemented in Demand Management Cloud, will demand history aggregate to All Other for non-Key Customers and forecast is also calculated for the All Other customer?

Content

My client has good sales history data for key customers (20% customers count for 80% sales - the 20/80 rule), the rest sales history at customer level is very sparse and not suitable for statistics. If I implement Key Customer option, will demand history aggregate to All Other for non-Key Customers and forecast is also calculated for the All Other customer based on the aggregate sales history of All Other? My client does not need detailed forecasts at customer level for non-key customers.