Capt Chambo
This is one of those areas that needs ICAO to resolve one way or the other. We should either all fly metric or FL. Having worked for many years in that in-between airspace where the ATCOs had to transition a/c from/to metric/FL, I know that it is another of those "holes" just waiting to line up to cause ..... And if we could get the politics out of the equation then the whole system would be a deal safer. Let's face it, the countries still persisting with metric levels are in the minority. In the meantime, fly safe when transitioning.
On the beach