I'm looking at the sfo-hkg flight in F on a 744 (Boeing 747-400) and noticed that the three seats in row 4 are categorized as P on expertflyer which are premium seats. I know the window seats in row 4 are bassinet seats but beign in F, does the extra room really make it a premium seat?

What makes the middle seat a premium seat as well? I've heard that the middle seat is the worst one in that section?