Just comparing this seasons stats with both Utah and Cle.
He's shooting 4.7 times less per game with Cle.
He making 1.8 less shots per game with Cle.
He's playing 2.5 less MPG with Cle.
He's shooting a better % over all, but a lower % on both 3's and FT's
He's not turning the ball over for Cle, probably because he only touches the ball to shoot and is not allowed to try and create a shot.
Best stat of all he's scoring 6 PPG less for Cle than Utah.
So if he's getting more easy shots playing with Lebron it's at a far lower rate and is not helping his 3pt%. I think his over all % is only higher because a greater % of his shots are inside.