Only speculative thoughts...
Sometimes short sales are priced under market to gain a lot of attention and as such multiple offers. Provided the house has value at $150,000 - he or she is hoping for you to be the "best" and not get bogged down in a multiple counter offer scenario, aka bidding war.
Ask your agent why they've chosen $150K. He or she is the best person to answer knowing the property, your market values, and competition.