Addis Ababa is 2 hours behind Karachi
Best overlap: 10:00 AM to 6:00 PM in Karachi is 8:00 AM to 4:00 PM in Addis Ababa.
Karachi and Addis Ababa overlap from 10:00 AM to 6:00 PM (Karachi) to the equivalent 8:00 AM to 4:00 PM in Addis Ababa — that's your meeting window. 8 hours of shared hours is more than enough — slot meetings wherever they're most convenient for the people involved.