As said above ... perfectly normal. Due to slightly different holds.
I can move my front hand very slightly away from it's normal position and the poi moves quite a way ( 20 plus clicks at 35 yards ). I can also put a wee bit more pressure on the pistol grip and again poi moves a lot. I have even noticed I can make the poi move sideways by a similar amount by putting more or less pressure on with the tip of my thumb ( pistol grip ).
So different shooters will hold thegun slightly differently and the poi will be different.