By my take of the original route description, this section of the climb is off-route, BUT, I would strongly recommend this path b/c it is protectable. I believe the FA party stayed at the mouth of the chimney till a ledge before cutting back into the chimney. Hard to describe this place. Glad to see someone else has had this experience.
We did the same thing. We made it to the ledge that i believe is on-route and when i looked at the 50' of unprotectable wide chimney that had to be negotiated I downclimbed and walked to the back of the chimney which led to some excellent climbing.