It will be considerably cheaper to get the works done during daylight. It is also very time consuming to have to return the RWY to operational condition at the end of each night's works, only to have to rip up the temporary fix the following night and continue the program. MEL, SYD & BNE do it at night because they have to. Looking at the AD layout, I do find it puzzling that the cross strip is out of action for the works duration. I would have thought you could get a lot of the main strip done before it would impact on ops on the cross-strip. The MOWP will tell all.