BPA CLIN...on an IDIQ contract?

I'm in the middle of a re-compete and in looking over the contract that is ending that I am replacing I see they have a CLIN on it called "BPA CLIN for FFP Calls". Some background info: This is a contract for facilities O&M services. They have a fixed price CLIN that covers all facilities O&M services so long as any single service required does not exceed $25,000. When they do have a single service expected to exceed that amount they have the contractor submit a fixed price estimate and then issue a "call" off this BPA CLIN where they have a bunch of money parked. I have never seen anything like this. "As-Needed" CLINs that follow a similar approach, yes, but in those cases we cut a separate  TO specifically for that as needed single issue with no parking of money, but to have a BPA within an IDIQ? Am I wasting my time worrying over bad wording and semantics or is this a jerry rigged situation? They essentially want a pot of money to bill as-needed services against as they arise but that essentially violates the no parking money rules. Can I set it up as a contingency fund situation or is that only for construction? Or possibly an "Over and Above Work" situation -  to cover what is over and above the Fixed Price CLIN? That seems almost perfect for this situation but we don't have something similar to the DFARs clause outside the DOD that covers that as far as I can find.