It would be interesting to learn more about the NAT level allocated.
Is the possibility of a fuel-punitive lower FL considered during the planning stage for normal NAT operations? Or is normal contingency allowance assumed to be sufficient for such an event?
Was the non-normal (sic) state of the 747 in question known to the Oceanic system before onward clearance was sought? If not, would the OEI status of the a/c have made any difference to the allocation of available levels when Oceanic clearance was requested? Or would the fact that no emergency was declared mean that the Oceanic controller could reasonably assume that the 747 should be capable of accepting whatever level it had been allocated?