Excerpt from CR - "For the battery test, we download a series of 10 web pages sequentially, starting with the battery fully charged, and ending when the laptop shuts down. The web pages are stored on a server in our lab, and transmitted over a WiFi network set up specifically for this purpose. We conduct our battery tests using the computer’s default browser—Safari, in the case of the MacBook Pro laptops.
During the tests, we set each laptop screen to remain on. We use an external meter to set the display brightness to 100 nits—a typical level you might use indoors or out. And, we turn off any automatic brightness adjustment in the laptop’s settings.
We also update every computer's operating system before we begin any testing. We began our tests several weeks ago, but repeated the battery tests using macOS Sierra 10.12.2 after it was released. We saw no difference in the results.
Increasingly, we see that the performance of all kinds of products—not just computers and smartphones—can be influenced by software updates. If Apple updates its software in a way that the company claims will substantively change battery performance, we will conduct fresh tests.
Once our official testing was done, we experimented by conducting the same battery tests using a Chrome browser, rather than Safari. For this exercise, we ran two trials on each of the laptops, and found battery life to be consistently high on all six runs. That’s not enough data for us to draw a conclusion, and in any case a test using Chrome wouldn’t affect our ratings, since we only use the default browser to calculate our scores for all laptops. But it’s something that a MacBook Pro owner might choose to try.
Consumer Reports has shared diagnostic files pulled from all three computers with Apple in the hope that this will help the company diagnose and fix any problem. We will report back with any updates."
Cursory glance says they didn't do anything they don't do with any laptop test. They sent their data to Apple so maybe Apple will confirm your theory.