Flown the 10 for a few hours (IP) and can only think it is to either stop a bit of PIO (moving left and right but having trouble stopping astern) or to shack your position once you've moved back to the centreline from out to the right. There was always a natural (if AAR can be callled such) push back towards the centreline if you wandered too far out to the side, and you would need to stop that movement when you approach the centreline in this case. And refuelling behind a 135 was always the devil's work!😰