And as for MDIs always lasting less than an hour.....
CC has a permanent MDI for all HONILEY and LISTO departures (1 per 3 on each route) every day between 0700L and 0815L.
I would like to believe that this was nothing to do with meeting destination whatever-it-is (and everything to do with protecting the sectors) but I'm afraid that I can't make that leap of faith! We are always under trenmendous pressure not to flow traffic in or out of CC at any time - but MDIs are frequently imposed during the traffic surges, and often for more than an hour.