The distros of your players is probably the reason. It looks like of your bench players Nieto is the only one with a high distro so he's taking a large percentage of shots and he's set to +1. Same goes for White in the starting lineup. Guards set to 0 tend to take the majority of their shots from 3, probably as much as 75% unless they have freakishly good LP, somebody like Hughes would fit in this category.