if I remember correctly, the "vendor bid" must be placed at least several days in advance of the auction itself, but yes can take place after the auction opens for the Signature Auctions. However, if you do this, Grey discourages your action and you do pay the BP (which yes, is like a sale. The house is still getting their portion).
You are not allowed to perform this action on the day of an auction by Texas law I believe as your bid is considered a reserve of some sort which much be disclosed in advance of final days bidding.
Concerning the Dietrich poster, IF the poster was bought back by the seller and the bid was $750 ending with BP at $896, that means the owner would have $146 that evaporated (he owned the poster to begin with, now he still owns the poster and is out $146 plus his other costs like shipping both ways. Figure $175)
so it is pretty clear that bidding on your own stuff, particularly in this case, is totally non-productive and I fail to see why anyone would practice this, whether it is allowed by law or not. If it was the case, after getting his $456 on this sale, his real value is less than $300. So my suggestion is that Heritage did indeed sell the poster and the new owner of the poster consigned it to the sale last week.
I actually had a conversation with Grey about this some time back and he pretty much explained that if you go this route, he won't be taking more consignments from you. so your fears are just fears.
Simes, not sure what you mean here.
I still wonder at their Secret Maximum bids. I had placed a max bid for some lobbies and in the Sunday night bidding after the closure of the week's bidding, my max was maxed out but not surpassed.
you can't bid after an auction closes.