Sniper Rifle Aiming Bug

Has anyone experienced where when zoom aiming and then shooting with the sniper rifle, projectile is way off? Even when trying to adjust it up/down (and the movement delays), it still goes to the same spot as before unless really moved a great deal, and then it's really off more. This seems to happen when aiming around edges of objects to take out a hiding enemy. Also, in ME1 & 3 (haven't really used a SR in 2), when aiming at a moving target, moving the thumbstick to adjust my aim is seriosuly delayed. The reticle doesn't move until I have move the stick a great deal, then when the reticle moves, it moves to how the calibration senses my stick movement location which is really fast. IOWs, I slowly move the stick left/right, the reticle doesn't move but when I hits the point where it recognizes I am moving my aim, it's moving fast unlike really slow if I just barely move the stick.

This makes playing higher difficulties hard and really hard in the Armax Arena where the phantoms recgnize my misses and they zap around to get me. Usually when hhitting them, it stuns them at first giving me a chance to react with a biotoc shot then a reload to hit again.

Note: this is using an XBSX.