Back in Apple II and macintosh days, Apple already had a history to incorporating special modes that only their hardware know how to use. For example, the Apple IIe card for macintosh had a special display mode that were not visible to end user if no special hardware uses it.
I noticed this charging irregularity where my 11” MacBook Air charged iPhone 6s Plus faster than charging through PC usb port. 10W output compared to 5W or lower. So yeah.