Not when you are shackled it doesn't. Setting aside everything else you wrote, being Immobilized is like having your ankles shackled to a ring in the concrete. If I throw a refrigerator at you, it's going to knock you down, not back...unless of course I throw it so hard your feet are literally left behind still shackled as your body flies backwards that is, lol. So no, If I immobilize, no targets should be getting knocked back when I put it all together in my head. Targets getting knocked when they are Immobilized seems very off, in a gaming mechanical sense and in a more reality sense.