Being in the construction game myself I was pretty sure this would happen for all stages looking at being released around the december mark, and acounted for a late release in Jan/Feb (im in stage 15).
The probable reason for the delay are time off for some of the construction workers and the recent rain we have been recieving causing havoc with formations etc.
I just hope we arn't delayed as much as some of the other stages have been, otherwise I may have to sneak in there on weekends and do thier job for them! jks