That shouldn't be correct,
All bids should have to be posted here in the public, otherwise it's not a valid bid, how should we know that's the truth and not something created to get the bid to jump up higher? I'm interested and even raising the bid higher then $100 but not until the bid is provided to the public. You said by PM, why cannot the person bid here in public?
I'll bid after I see the user you said PM'd you that bid for $100.
I'll only bid if it's public.
My bidd: $120 - after it's provided to public, otherwise $90