Like most other studies, they think they are right... until someone else comes up with another study to proclaim that it's not what the first study suggested.
Keep the extra evening daylight. We will all adjust and we will get more things done in the evenings. The problem is the jumping back & forth with our body clock that is creating the issues, NOT what time we wake up and go back to bed. Let's just set the time where we can get the most accomplished and keep it that way.