I would think the only reason to change the live page to "under construction" would be to let us know some kind of big change is coming. They could be doing something like simply reformatting their website, but in a big way. Changes to the webpages, information, adding or removing products can all be done behind the scenes and taken live in a a click. I would be surprised if "under construction" did not mean a big change somehow, but that "how" is all pure speculation. All in my opinion of course!