Yes he's a STH & it was definitely 10 points. No idea of the rationale behind it. As Thunder Bolt suggested earlier, it may well be a moot point now that the loyalty points system has changed.
My mate definitely lost points going via the Exchange - it was clear on his record (that he did not get any points for that particular game). I agree that with the new system in place it may no longer be the case and that my prior post should have said 'may lose points' rather than 'will lose...
A mate used the Exchange last Christmas to sell on his seat for QPR at home. The loyalty points for that game (10 I think) were deducted from his total. Not sure this is very well known or communicated. I assume it is still the case.