This is very typical with Freddie Mac. They do not take much less than asking price on their listings. Their listings are usually in better shape (it sounds like this one may be the exception) and are usually priced correctly. I will say that I've consistently had the experience you describe. Usually you have to make 3 offers to get them to come down (and that is assuming that in the days it takes you to make 3 offers that no other offers come in). With one of my clients this summer, the home was listed at 89k. We offered 84, they came back with 89. We offered 85, they came back with 88. We offered 86, they came back at 87. We accepted 87. It all depends on the asset manager, but in general they aren't taking 22% off the current list price (what your offer of 14,000 represents on a 17,900 list price) - more like 1-3%. Now that isn't to say that if it sits for another 30 days that the list price won't come down to 15,900 from the current 17,900, but then you run the risk of someone else making an offer.
I hope this helps; Best of luck to you!