I am confused about something. The following link shows the domestic first seats used on UAs 757 and 767/777 two class planes:

http://www.united.com/page/article/0...e=RelatedLinks

According to seatguru, however, the width of UA F seats on the 757 is reported as 20.5" but the width of F seats on the 767 two-class is only 19". Now I can understand how the pitch can change from one plane to another, but how does the width of the seat change? Are there really two different domestic F seats that differ only in width??