Another thing to consider is fuel dumping...if they did have a fuel balance problem.
All the tip fuel in the 35 can be dumped in 5 mins. If the tip tanks are full that decreases landing weight by about 2400 pounds.
It seems as though they were at Max Landing Weight of 15 300 which equals a ref of 129 and a 20 flap ref of 139.
Although I may have lost something in the translation, it seems like this wasn't considered....easy to second guess, but something I hope I'd consider in this situation.