Well first off no one knows exactly what the date will be for Transformers. Contractors have been given a date Dec 2013 for which the project MUST be completed by. The deal between Universal Hensel Phelps and PCL is an incentive laden deal. June/July are target dates the contractors are aiming for to get a lot more money. Meet the rush deadline and get paid the big bucks! Miss your deadline on the back end and face a penalty. It's like this with most major construction projects. Universal is throwing huge capital into Transformers through incentives and overall construction costs via round he clock construction. In the end though most of the increased payroll these contractors are throwing into this project are being fronted by them in order to get their massive incentives. Universal isn't the only one who wants this project up and running as soon as possible.
As for Potter I think late 2014 is possible but my money is on June 2015 for a grand with softs a month or two before that.One thing many seem to forget is this expansion is much larger in scale than phase 1 in every way. The sheer amount of detail work, testing, and changes required once construction is completed will also mimic what happened during the end of phase 1. It has to be perfect because yet again the world will be watching. And not only will they see Potter, they will see an entire new park. People are going to be blown away when this project is announced next year as Universal is raising the bar they set in Phase 1 to another level.