That's not necessarily surprising, Brunt and Solano were set-piece experts and with Beckham (or Giggs) about, he was never going to have that opportunity. United were very much a traditional 4-4-2 team with Beckham and Giggs delivering from wide and into Yorke/Cole/RVN etc from the end of the 90's til the early 00's. That ties up pretty well with his best numbers in goal terms when he used to arrive late - he was very good in the air for his size.
I do think he went up another level when their style changed in the Ronaldo/Rooney era when he sat much deeper in that Pirlo/Xabi Alonso role. His ability to dictate the tempo of a game was something else.