Hi,
I'm not sure if this is very helpful but I did offer on my current house, it was 5 years ago and things were starting to fly off the walls then. I offered 3k irish punts lower and the builder was delighted even then. I am currently in the process of buying a site for a selfbuild and was recently wondering was I mad to be taking on all this work so I went out and about to see houses similar to what I'm looking to build. I met with alot (4 or 5) of the developers and the asking prices were from 600 to 495k........... they all were " sure make me on offer" even one local builder who I just rang and said to him " so what are we really talking" he said a price 15k lower that the sherry fitz advertised price ( no offence to them their only doing what their told) and I didn't even meet this guy, just on the phone. So I'd say totally go for it. If your a ftb or have sale agreed even in a boyent market at this time of year your in a good buying place, in this climate your a developers P Diddy in Wiers!!
Best of luck