The problem is not one of the number of crew in the area but of enough ventilation for smoke removal. Therefore dispatch with CAC u/s and planned requirement for use of OFAR requires fuel planning for Max FL350. I would also suggest the planned use of OFAR and CAC fails in flight sensible to complete required rest as soon as practical descending to or maintaining FL350 or below and then climb to normal cruise. But that's just me, it only says prior to dispatch.