if at the time of feeding batch details software also ask for sale discount and user needs to disable it then this issue can be resolved: 

• Go to Masters > Marg Setups > Control Room. Press Enter.

• A Control Room window will appear.

• The user will select ‘Search in All’. Press Enter.

• A Controls window will appear. Then user will Search “Batch wise Discount”.

• Now click on ‘Accept’.

• A Batch wise Discount window will appear.

• In ‘Batch/Size wise Discount % Y-Yes C-If Party/Company 0 N-No’, the user will select "N".

• The user will now press Esc key twice .

• Click on ‘Yes’ to Save changes.

After following the above steps discount option will get disabled from Batch detail window.