For combo, the dose 525 vs 700mg is not as important. But since 700mg important for mono, maybe they are waiting to see with that. Because mono is much bigger than combo and they are close to getting a FDA decision on both dose and mono, I could see them waiting for those decisions this close.
I'm not concerned with the 700mg safety, here are the early results from January. No escalation of safety concerns with dose increase on this interim data.