It is perplexing.
But the one thing I find funny is that players run faster on turf then grass. Seeing how he was outside, I'm going to assume he was running on grass. So he's probably faster than that time.
Also it is true 40 time isn't always the biggest deal. I feel it has varying translation depending on position. He's a pass rusher, so quickness combined with strength and moves are more important. He won't be dropping into coverage often, and if he's really a liability he can be strictly a pass rusher. But that would mean a one dimensional player which would be important to take into account if drafting.
Now it might hurt him against say the Wilson's and Kaepernick's, but he should be plenty quick enough to get to most NFL QB's.
Personally I think the best available player will be on the OL. BPA means if Warmack is available, he's the BPA and at a need position.
I'm wary of drafting someone to only be a pass rushing specialist, and if I was, I would want someone faster. I mean what is he about the same size as Bruce Irvin but ~1/2 second or more slower? Ahh Irvin ran a 4.50. As much talent as he flashed, I still think he was a reach for where he was selected.
Though pass rush is very important, so I can understand these premium type moves. Guys that are one dimensional to me scream lower draft position. Blue chippers are supposed to be jack of all trades, king of all type players. Specialists imo belong in the 2nd round or lower. At the very best bottom 1st round.
Now I don't know a ton about Jarvis Jones, so I can't tell you how he covers or how he handles the run, but if all he does is rush the passer, I say pass and take a true blue chipper. Especially when the QB's in OUR division mean IF he IS slow, then it would show up MOST against Kaepernick and Wilson as they just bust it around his rush for 40 yards.