Soak dried beans: longer is not necessarily better

I soaked read beans over night this time but they didn't turn out as good (and easily cooked) as before, when I just soaked them for a couple of hours. It says here that "The best way is to put them in cold water; bring them gently to a boil and then with saucepan off the heat, allow them to remain in the water for 1 to 2 hours only. "