The arm bar in Perry’s kids swing flat, with a upright posture. The swing doesn’t follow or I guess it does, follows a upright posture, anyways there is no tilt in the swing, good posture, so therefor the swing doesn’t follow a tilted posture.
His kids do swing well, they just have poor posture. Same swing plane actions in most kids who bat drag, loop, DBSF, and cast. Then you have the kids trying to create a swing plane with their hands/arms. These kids can have poor posture or at least a barrel path out of plane.
Same position attained, and different hand position and barrel positions, just two different styles. Cabrera has the figure skater effect happening, or closer limbs, tighter arc.