The bank will NOT negotiate with you directly, so you must use the services of an agent, whether that be the listing agent, a transaction broker (representing neither side over the other), or a buyer's agent.
The downside of buyer's agency? It is a two-way street for the buyer AND the agent. They both have to have loyalty to each other. That means you don't get a buyer's agent if you are shopping around and calling every agent you find. THAT is the downside for the buyer. For the agent, the downside is that they have a higher level of legal responsibility to the client than to a mere customer, and they don't get paid a penny more. So now you have a straight-forward answer and can put that issue to rest!
I'm not sure what point Viktor was trying to make, but the bank has listed the property, and that means they do NOT want to deal directly with buyers. The bank usually is a corporation not even in the state where the property is located, and they NEED and want the services of an in-state broker. The bank has already committed to pay commission (REAL ESTATE 101: all of the commission is paid to the listing company, which then pays the selling company).
Now let's deal with that escalation clause CharlotteNC found on the internet. An REO seller does NOT allow customers to write their own addenda. NEVER! If they did not originate the form, the REO seller does not sign the form. That, quite simply, is not negotiable.
The REO forms and the REO process do not incorporate a way to do an escalation clause, so you are dooming your offer to failure if you try to force the issue. The seller does not care if you get the best deal possible without paying more than you have to pay. That does not serve THEIR purpose. Why, then, would they accommodate the process? The answer is that they won't.
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REALTORŪ, Broker/Salesperson, GRI, ABR
REO listing/selling since 2004; BPOs