I really have no idea what this means. I have a 23 in. Samsung running off my MBP 17. The laptop maxes out at 1050 and the Samsung at 1620X1200. I run it at 1920X1080. If it is set to extended desktop, it fills both screens at their native resolutions, even though they are different. If I switch to mirroring, then the laptop display is centered at about 80% of the Samsung. I think the box is backwards.
Dale