Sinamics S120 drive tuning question

One table is operated by ac motor and motor is drive by Sinamics S120 drive. The table carry steel coil. and the table went through 4 position(extreme left, 2 middle and extreme right) and it start from extreme right then stop first middle position, then stop at 2nd middle position and then it stop extreme right. Whenever table carry less than 20000 Kg coil all position it stop are ok. But when table carry more than 20000 Kg it stop 2 middle position are fine. But at extreme right position whenever it stop it's position is little less.

Could anyone suggest what parameter(P, I or what )in drive i need to adjust. and how to do that.
Your reply will be great help.

Are you saying it stops too soon or overshoots the position.

How are you measuring the position error - from encoder feedback or direct physical measurement with a rule, DTI...

How is the S120 configured - speed control or basic positioner?

it stops soon(20 mm difference). From encoder position is measuring .
It is configured as sensorless vector speed control.