I can't believe I'm still at this but...
Avrodamo, you are wrong, it clearly states
"Prior to operating a ULR flight departing Dubai, all crew members shall be acclimatised"
It does not say you must be acclimatised to DXB, and that's the key part of the wording, it's deliberate as its written to give flexibility and clarity for this statement.
"For the day of actual operation a crew member who remains acclimatised during leave is not restricted by c. above"
Which coming full circle means you have to understand what it means to be acclimatised or not, and thus refer to the definition.
Clear as day now?