The so-called "cooking times" seem short and very fast, but they don't take into account the time it takes to build up the pressure, which is often longer than the actual stated cooking times.  For example, to cook potatoes the time is given as 8 minutes, but it takes 10 minutes to build up the full pressure before you're to start timing, so it's really 18 minutes.  Plan accordingly.  It's even worse for recipes done in parts where you cool it down to add a second step or things that would over cook if added at the beginning - then you have to build to pressure twice.