You can add a couple ticks for the home-feild advantage...

Patrick Willis LB - Willis (6-1, 237 pounds) ran the 40-yard dash in 4.37 and 4.38. He also had a 4.37 short shuttle and 7.10 three-cone drill. He stood on his numbers from the Combine for the rest. He had a phenomenal workout and clearly made several seven-figure increments in his rookie contract.

link: http://www.nfl.com/draft/analysis/individual_workouts