I hope no one minds me adding to this post rather than starting afresh, I thought it might save some duplication.
My hub (Well one of them
) is ready for an oil change, and a while ago while re-reading the excellent "Living with a Rohloff" I noticed Andy Blance does something a little different - After a double flush, he adds 25ml oil, gives it a mix and then removes 18ml. If I've understood it right, that only leaves 14ml in the hub (7 clinging to the parts and 7 free) but in theory that will be cleaner, fresher oil than what would be in there by any other method.
Anyone doing this? Can you think of any drawbacks? I've always been of the opinion that the service interval is way to short from a lubrication POV and the purpose was to flush the hub. I don't have any evidence for this, though if it was required for lubrication doing so at a maximum 12 month interval, regardless of use, would seem pointless.