The native resolution on the 16' is 3072x1920 So after a few generations (I dont remember when), apple started using the first of the 2 More Space scaled options as the default for display.
To me and I suppose to the majority of the people out there, there is no real difference between this and the other More Space options when selecting scaled resolutions. To many people this looks sharper and better than the other scaled resolutions. On the first generation 15' retina, this corresponded to looks like 1440x900 which was half of the native 2880x1800 resolution. When apple launched the retina macbook pros, they used a 2x scaling option as default.
