Hi,
You can use condition exclusion functionality to meet this requirement.
Define Condition Exclusion group and assign it to condition type ZSRP.
Maintain this group to your pricing procedure by selecting option B - Best condition within the condition Type.
Now raise a sales order and maintain ZSRP twice.Though system shows both only condition with least value will be active and Assessable value will be calculated only on the smaller value.If you maintain the same value for the two times, then also system will calculate Assessable value on one line item only.
Please check and update.
@ Amitesh - Even if you maintain condition record for JASS, System will take the value of both line items for JASS.Please check.
Phani Prasad