Unless it's enforced to share information properly, if some people are in an office and others are not, there are two classes of political animal created immediately and that will affect everything.
Unless I missed it, he didn't get into how variable work really is... this 10h thing is kind of a crock for the kind of work I do anyway... sometimes you are blocked on the one thing you have to be doing and it's difficult to focus on things that are of secondary importance just because you should be working. Other times you're being paid, but there's nothing to do for one reason or another. You can usually find useful things to do but at these times, they already know the situation. They want you to just note it, keep your head down and do something you can do yourself that should be somewhat helpful, and pick up immediately the thing is unblocked.
It's just not always possible to move things forward for 10h each day... be transparent about it. Sometimes if it's an architectural or philosphical issue, you need to study it and then do something else while your brain thinks about it. Some days nothing is going to move forward no matter what you do because of your personal state... you learn to recognize it and let it go... tomorrow or the day after you'll be back in triple force and more than make it up. The people who are paying you usually care about results not hour by hour but week by week. So long as it's all happening on that scale everyone's happy.