With ref EK and the 772ER, I asked the question on a certain other website, and got the following reply;
On the NCL-DXB flight the TOW will be 246T, this is based on a MZFW of 195T
On a perfect day with a Temp of 15c and Q1013 the RTOW will be 253T. (MAX TOW 267T)
This means the aircraft will have a under-load of 7T.
Dunno how true that is though...
Anyway, EK have A330-300s on order, I would expect that they would be the next a/c type the route see's (unless it gets dropped).