It isn't that difficult for people to have different opinions on a player. One of the players on my son's team at his first showcase was a sophmore who we had known for years was a terrific hitter. He'd been one of the league's best hitters in a league with quite a few 90+ throwers. He had a poor showing at the showcase and was rated a 7.5. He didn't have a strong arm and it was below normal that weekend. He had decent running speed but nothing spectacular. I didn't see his BP but he struck out against soft stuff and he struck out against hard stuff in games and didn't get a hit the entire showcase. To be honest, giving him a 7.5 rating took some projection because he didn't perform anywhere near that well. When my son was rated a bit higher than this player we had a bit of a laugh because we knew the kid was good, really good. Not long after that he got an offer from a major D1. A few months later he showcased and was rated a 9.5. Today I assume he's almost done negotiating his first round deal.
I can't imagine that any two coaches could have had the same impression of this player from that particular showcase. Tons of talent/projection, some obvious weaknesses and performance that didn't match the talent.