Hello Ravi,
If you are maintaining condition record through VK11 for condition type JMOD, then the value should be in parentage, not in currency. The condition type should be maintained in V/06 as Cond Class:D, Calculation Type:A, Cond Category: As per your business requirement. The Amount/Percent tick should be active.
The condition type JMOD should be listed in procedure TAXINN.
Same value should be maintained in FV11 for the Tax code:A0.
Regards,
Rahul Hande