It seems to me that with the battery sized the way it is now, at 49Whr in the TouchBar model, 10 hours of battery life doesn't add up except under the lightest of usage scenarios. I'm sure that the efficiency of some components has been improved, but I'm skeptical they've improved them enough.
My 2015 rMB typically uses between 4-5W under light use, at ~60% brightness. With its 41Whr battery that's good for over 8 hours of use even at 5W. The new MBP has a larger, brighter screen, a much more powerful processor (28W TDP vs. 4.5W TDP), two fans, the TouchBar hardware, and two Thunderbolt daughter cards, among other things. So with all those additions, it needs to use the same 5W as my rMB in order to hit the stated 10 hours of battery. Seems unlikely.