Let me preface this by saying that I have NO experience as a realtor or as a title agent... That said, the seller has paid a fee to the agent for services.  The agent, in turn is taking his/her money and giving it to the buyer.  The seller did not give additional funds to the buyer - only the commission fee.  What that agent choses to do with that money seems, at this point, to leave the responsibility of the seller.  I'm not sure how that fits with reporting on the HUD-1, but since there were no additional funds collected from the seller, I don't think it is the seller's concession to the buyer.  I know that if a buyer receives funds as a "gift" from anyone, the lender is supposed to be made aware, but I'm not sure this falls under something the actual seller gave to the buyer.

When I bought a condo years ago, my agent was a very good friend.  He purchased a home warranty for me - would that need to have been reported anywhere, because I don't believe it was.  Maybe none of that matters since he was the buyer's agent.