Your question revolves around moving funds between CLINs on an IDIQ.  I am going to make an assumption that the funds on CLIN 3 are now expired, if the Appropriation is in the Expired phase it is not available to be obligated for a new effort.  Since IDIQ contracts are normally obligated at the DO level, then I believe this would be a purpose statue violation as well as a Bona Fide Need violation.  From the limited information and description you provided, not only is the money on different CLINs, but the intent is to use for a different, unrelated task which would be the Purpose Statute violation.

I strongly suggest that you contact your local Comptroller/funds certifier and/or Legal Office to discuss this situation and receive additional guidance.