The problem with figuring out anything to do with the FBI is its disjointed and internally highly competitive nature and with the redactions after skimming through it, I can't tell with 100% certainty who exactly was making the 702 requests, whether it was NSB at Quantico, Headquarters, or one (or some, or all) of the field offices. The field offices are their own personal little kingdoms and they don't cooperate with each other routinely, much less with HQ or Quantico unless it suits them.
It shouldn't surprise anyone that FBI was/is part of PRISM or ECHELON or any of the other programs, though I have my doubts Criminal Investigations really did much with it due to its inadmissability outside of Espionage investigations, I'm sure it was used to point toward admissable evidence though. I might be wrong, but FBI's culture is idiotic and self-defeating alot of the time.
You'd have to FOIA information directly pertaining to NSB and CIB's information sharing to find out for sure and good luck with that.