Just looked at today's plan for MEL-PER. 8T is 120 minutes. Thought it may have been more but there you go.
When I looked at the LHR- PER sector a few days back they were carrying a full load of 230+ pax and arriving in PER with about 5.5T. They still had a few ton below MTOW so could probably have put a bit more gas in it. Still, 8T over the top of PER doesn't give you too many funk holes if there are TS around. At least there's normally not much chance of FG in PER in the middle of the arvo!