my cousin called me this morning around 5am, and i asked him, is it a free call that the time has passed 4.30am. he said mtn midnight call ends 5.30am in north. now my question is this, if this country is one how come mtn has different tariff plans? midnight calls end 4.30am in the south and 5.30am in the north. is this not a two different countries. mtn why?