This can probably be explained as:
-They aren’t training with the people who got them to 6.5s in the 60m
-They haven’t been competing and simply aren’t in 6.5 shape at this moment. They have both typically opened up 6.6high-6.7 and then dropped time after getting in races and getting in better shape for the 60m.
-The 40s are essentially handtimed and quite inaccurate and imprecise (as in, there are large variations in addition to being inaccurate)
-A lot of guys have good 30m or so ability even if they don’t run track and most of the truly fast guys in the NFL can probably run 6.7-6.8 first time out (most of these guys ran track in HS and went 10.6-10.9 anyway, which is close to that, combined with the fact they have relatively better acceleration anyway). Even some questionable S&C programs do a fairly good job of getting people to run a fairly fast 30m. Not 6.3-6.5 60m caliber acceleration, but better than would be expected because of the nature of their training and the fact they are very gifted, IMO. Very few are going to be in 6.5 shape, even if they were doing track in college, but it is quite reasonable to think many would be in the 6.7s and even 6.6s when fresh and after some races if they dedicated themselves for 2-3 months when healthy.