Here's another of my bizzare assumptions. Let's assume the pilot discusses preferred altitudes enroute with FSS, let's say upper level winds suggest a smoother ride at FL250, instead of say 18 000 feet. If the company filed for say 19 000 feet, and the pilot prefers the higher altitude, he'll probably ask the FSS to re-file on behalf of the company, forward THAT to ATC CTR who will amend the flight plan, read the newer version upon ATC clearance. Is that correct?