Seems to me that the reason for the two drop zones into one landing site is linked to the ceiling (as limited by Q41, which starts at FL065). The temp section of Q41 to the west of the landing zone means that during times when this is inactive, a jump from FL120 may be possible. But it's never possible directly over the planned landing site.
On this basis, I would imagine that the western jump zone would only be active when weather (wind) and Q41 allow. This is just a guess, I don't know the area well and so far I've never jumped out of an aeroplane. Maybe someone who knows more can clarify, perhaps even Mr Ivory?