I think that the idea that they grade friendly pieces is probably a bit of a myth - they wouldn't have a business if there was evidence of this - I know that there are rumours that regular graders do get preferential grades but again I think they are probably unfounded
In terms of re-grading - both companies are happy to do it (for a fee!) but your chances of getting an improvement in grade are probably low as it is likely that with age the item has got worse - especially if it has been moved around a few times
Also, I believe that the general consensus is the opposite to what you have written and that UKG are harsher with their grades than AFA - so if that is the case then sending an AFA piece to UKG might see a downgrade
Anyway, hopefully this is seen as factually correct and not in anyway anti-grading as I would hate to be accused of being biased :roll: