1) it's a hypothesis, not an assumption.
2) that exactly was my question if that is really the case. there seem to be conflicting information about that in the above posts, that is why i asked.

the way i read the posts, thois is stating that everything will be collected in the currency the airport/airlines charges the tax/surcharges. if that is the case, 2) is irrelevant.

zombee and calchas seem to agree that everything you pay will be priced in EGP. Then the question then is, if you have a fee occur on another date than the date of the purchase, which FX rate will be used. The FX rate of the date i bought the ticket or the FX rate of that specific date when I do get charged because I request a change in my itinerary. It is completely irrelevant if the rate goes up or down or which currency i hold