He might be confused by the fact that 16:9 gives you a wider physical size than 16:10 for a given screen size (since screen size is a diagonal measurement). The pixels are just stretched out a little more horizontally - you don't actually get any extra information displayed.
A 16:9 screen has less vertical resolution than a 16:10 screen of the same inchage. The pixels are definitely not stretched out at all, pixels on monitors are square.
