The CG just combined some units to form Sector commands, that's all. Stations have always been under their commands, kind of like a fire battalion of a major fire department. If you have any other CG questions let me know. I'm active duty and work at a sector. Command structure of CG:
Headquarters
Area (Great Lakes falls under Atlantic AREA) These will be going away soon to form one Operations Command, or OPCOM for PAC area and LANT area.
District (Great Lakes is D9) in Cleveland.
Sectors (Lake Michigan in Milwaukee, Sault Saint Marie, Detroit, Buffalo.
Also, all of the above levels of command have a 24/7 command center, including HQ.