This is the key point I think. One of the things I discovered early in my career was that I didn't have any trouble at all making decisions. People would ask for a decision and "Blam!" I'd give them one. This was apparently a super power and it served me well until I got to be a bit more senior and one of my decisions cost the company more than they expected it to cost. I got called in to talk to the executive vice president to explain myself. I was scared to death. As it turned out, he was ok with the unexpectedness but wasn't ok with the fact that my boss' boss didn't know why we had decided that way. I needed to keep folks in the loop so that they could keep up, but I also had to own up to my decisions.
As the stakes go up, and you think "if I make the wrong choice here, we're screwed!" you can get frozen into inaction. If you can say, "If this turns out to be the wrong choice we'll be able to tell because this, this, or this other thing will happen and then we can move on to this other choice." it can give you the courage to move forward.
I agree there aren't rules here, but there is reasoning.
I guess the moral of the story is that the truth is a tool.
Also I wonder if the (relatively white) lie was necessary in this case.