I'd be sure that communciation between buyer and seller is clear so that problems can be avoided.
For instance, and I'm not trying to take issue with you here, but I have trouble understanding about half of your initial post- lots of it is unclear and difficult to understand - then add in the numerous abrieviations used which people might also not be familiar with.
Use your judgement of course, but be careful about burning bridges.
A while back(years ago) I had a negative feedback left on my feedback thread because the user was upset that his deal with a completely different board member fell apart-of which I had no part in what so-ever..
The funny part is he never did leave the user that "screwed" him a negative feedback, just me - because I'd had a succesful transaction previous with the same user.