The door lights for DND/Make up room are not connected to any master system.....it is just to notify the room attendant in case the door knob sign goes missing. I have seen a couple of hotels in Hong Kong that feature a DND mode on the TV but haven't used it myself.

If a specific time for making up the room is needed the best time is to tell the Front Desk on arrival. If you frequently stay at the hotel then it will be in the guest profile and they should automatically do it.