APS (aircraft prepared for service weight) approx 170 tonnes.
Fuel FRA-SFO approx 120 tonnes.
Payload-no idea,pax and cargo between zero and 60 tonnes.
Max landing weight 269 tonnes,maybe 287 but unlikely,usually freighters are the heavier.
Perhaps 320 tonnes at start.
! tonne for taxi
10 tonnes burnt for takeoff first 45 minutes
So likely 40 tonnes over max landing weight without dumping.
Fuel dump 2.5 tonnes per minute,so 10 mins 25 tonnes,15 minutes 37.5 tonnes.

Seems about right on ballpark numbers with unknown pax/cargo figure.
Dumping is possible at 4000'
If it was a bomb threat they may not wish to climb in case of a barometric trigger.

Just a few thoughts from me.