I would just lie to add that you can successfully shock pasta in water that you are planning to use immediately. I worked in the restaurant industry for years, and I always shocked the pasta for consistency reasons. The trick is to flash heat the past just before serving.
I cook the noodles to a perfect al dente, shock the pasta to firm it up slightly, and then drop the pasta in a hot water bath for one minute before plating. I also season the water with a touch of sea salt and some EVOO to give the pasta that perfect flavor. The pasta is always perfect whether I serve it five minutes after being cooked, or five hours after being cooked.