That article was a little strange. Essentially, he said that Bolt is .05 seconds faster to 40 than Johnson is. He placed Johnson at 4.24 versus Bolt at 4.19 but the whole crux of the article was it was a ridiculous mismatch and Johnson was 'football fast', not 'track fast'. I don't see that as a big mismatch.
Not to mention, don't they launch differently at the combine. And what about surface. He seemed to leave a lot of things out.
The trainer also said all these 4.4/4.3 guys were running north of 5 with different timing. But for Bolt, that time was only worth .15 seconds, but it cost them over half a second. They must be really slow to start running.