There are certain conformities in any business, and real estate is no exception -- almost. When a seller wants to sell a home and enlists the employment of a real estate broker or agent, there are business formalities that are always followed. There is a written representation agreement between seller and broker for the broker to market and sell the property. Likewise, there is a written agreement between buyer and representing broker in all but the most primitive of areas.
When the buyer wants to make an offer, the appropriate forms are completed and signed, and they are sent to the broker representing the seller, or if physically possible, the offer is presented directly to the seller by the buyer's broker or agent. The seller either accepts or rejects the offer. If the offer is rejected, the seller may make a counter offer which puts the two and a half options in the buyer's court.
Counter offers are sometimes more in the form of discussion, with proposed terms and numbers passed between the principals through their agents. Sometimes each proposed change is accomplished more formally by documenting each in writing. I am comfortable with either way of negotiating a final agreement, and it is usually agreed by both parties just which style is chosen.
Then there's the banks. They may be too big to fail, but feel free to fill in the blank space, too big of a what??? There is no logical explanation for the procedure established by someone whose native tongue is .XLS that the bank only counters verbally but will not accept a verbal counter to their verbal counter. When asked to put their counter offer in writing, the answer is, no. It is simply not done.