If 1800 MHz spectrum is available as well, then they should take that into account as well. Surely Egypt won't remain a GSM 900-only country as their networks grow.
http://www.gsmworld.com/roaming/gsminfo/cou_eg.shtml
I also wonder how quickly TIM Egypt could be up and running since they would have also to cover some areas in the deserts which surely isn't a task completed overnight.