Enhanced Scan came out not too long ago through an update if I recall correctly so there may not be anything in the manuals about. Best I can recall Enhanced Scan basically combines Channel Scan, Priority Scan and Group/Zone Scan.
If you use Enhanced Scan, having the Scan List, not just the Channel Scan List, menu item available either through the menu itself or a programmable button really helps. Scan List will show all channels in every group/zone that you have selected as scannable so when you enable Enhanced Scan you can see all the channels that will be scanned throughout the radio.