Egypt does not price household electricity in simple blocks. Your whole month falls into one consumption band, and that band sets the rates for everything you used — so crossing a boundary reprices the month, not just the extra units. Above 650 kWh the entire month is charged at a single rate, which is why one extra kilowatt-hour at that line costs about EGP 370.
The figures here are EgyptERA's household tariff («الاستخدامات المنزلية»), in force from the April 2026 consumption month. The regulator publishes them in piastres per kilowatt-hour; they are shown here in Egyptian pounds.