This issue appears due user using net rate billing and that is not possible to remove net rate from all bills one by one then user will follow the below steps to resolve this issue:-

Note:-Firstly user needs to take backup before use this option.

1.Go to Reports > Management Report > Utilities > Structure/Junk Verification > Direct Command> Direct Command window will be appear > Enter here password as Current Date in a Reverse form(yy/mm/dd)> Command window will be appear > Enter command SELE DIS press enter and type BROW > Then click on Run > Dis file will be open > Press esc key.

2.Then type  REPL ALL  MISC4 WITH SUBSTR (MISC4,1,17) +'N' +SUBSTR( MISC4, 19) and then click on Run.

After following above mention steps cursor will wait on discount in all bills.