I hate to disagree but BOA or any other bank has more to be concerned about than the person trying to buy the house. They have zero obligation to the buyer.
The term "short sale" actually is slang for the current owner attempting to sell their current home, which has a mortgage on it, and pay less than they were contractually obligated to pay. Meaning, if they owe $150K, because they agreed to pay that much back to the company (i.e. bank) that paid the previous seller for the home... they are looking to pay back less than the balance owed.
In reality, that's why I said I am surprised that there is anyone needing to do a "short sale" in this hot real estate market. I imagine that the home had major deferred maintenance or some other issue that the current owners could not take care of. The only other likely issue is someone who is severely delinquent on their mortgage and have incurred a large amount of past due interest and fees, maybe even legal fees. Usually, if someone can't pay their mortgage, they can't do repairs and maintenance on a home.
The simple solution is to agree to the sales price and pay the difference owed, or obligated to, back to the bank. In this case BOA.
Again, it's easy to make BOA out to be the bad guy in this situation. But, in the end, they will be the one on the losing end of the transaction.