HPSOV, I allow 2 tonnes from Desdi/Bubin for a long way round approach. (You might - stress 'might' get away with a little less on a straight in, but don't count on it, for ‘straight in’ approaches frequently involve 90 degree or even larger turns away from finals.) Thus, my 'panic' figure, at which I’ll be declaring an emergency if I haven’t started the approach if I have committed to Dubai, is, as it is for you, usually around the 5.2 to 5.5 tonne mark, depending on my final reserve figure.
When you consider that virtually every EK 777 burns this much between the hold and touchdown on virtually every approach into Dubai whenever there is holding required, it makes a complete mockery of letters from the P.T.B. urging us to minimize unnecessary fuel burn. They could improve their bottom line on fuel usage exponentially with one meeting with UAE ATC insisting that this problem of early/slow descents and cross country marathon vectoring all too often with flaps extended be sorted out without delay.