Although the listing agent can legally represent both the seller, and you as the buyer, in New Jersey, (calls disclosed dual agency) I still agree with all the other agents that the listing agent acting also as a buyer agent has split fiduciary duties to BOTH the seller and buyer. These limitations are listed in the "dual agency agreement" you SHOULD be signing before entering into this type of transaction.
It doesn't serve you any real purpose to contact a listing agent to buy their listing, who cannot always legally advise you as well as if you had your own buyer agent working for you. You don''t save money since the seller pays commission anyway.
Imagine if, during the attorney review process, both the seller and buyer were using the same attorney...you'd say conflict of interest, right?
Short sales are another matter. The sale price is set by the bank, there are usually no inspection issues corrected, so the "dual agent" really doesn't have the need or opportunity to advise you on price or counsel you after an inspection.
Not the same with a "regular" sale. Get yourself an agent from a company OTHER than the listing company and proceed that way.