The AIM refers to the phraseology "cleared...as filed" for abbreviated IFR clearance, conditional on the FLP not having been amended since it was filed. This caveat raises the possibility that "via the flight planned route" could be used whether or not the current flight plan was as originally filed, but I am not sure....
Edt: According to Doc4444 The phrase “cleared via flight planned route” may be used to describe any route or portion thereof, provided the route or portion thereof is identical to that filed in the flight plan...and... The phrase “cleared via flight planned route” shall not be used when granting a re-clearance. Therefore I think the two phraseologies "as filed" and "via the flight planned route" are equivalent.
Last edited by oggers; 10th May 2019 at 18:57.