Shipyards aren't solid steel all the way through y'know. If you took a giant trash compactor and crumpled up the yard, it would only probably have about 1,000 meters worth of solid metal total, if even that.
If a planet can only support 15,000 meters of mantinence, and a shipyard/construction yard is 40,000 meters, then how can a single planet play host to up to 6 ship/construction yards?
Actually Grevious, since Ahnk was the only one who read all the rules, It can be considered that Ahnk and only Ahnk owned the four groups, and owned the staff it's self as well.