AF Microadjustment

I have three identical cameras, Canon EOS 1D Mark IVs, that I use for my work with South of the Border Volleyball Vacations. One of them consistently produces photos that are less in focus than the other two. I looked online and the suggestion was to try the AF Microadjustment setting in the autofocus menu. The shot on the left is -10 while the shot on the right is the maximum of -20. The right looks sharper to me (especially when zoomed in to 200%) so I'm going to try using that setting for a while and see if the photos improve.