Don't get hung up on price per square foot for detached residential construction - at the very best it should be used only to set the maximum parameters of any value range discussion. The reasons are many and it would benefit you to hit these links - http://www.trulia.com/blog/hank_miller_-_associate_broker/20 and http://www.hrmiller.com/price-per-sq-foot.asp
PPSF works with standard buildings - condos, offices, retail, etc but there are always variables to factor in.
If you're buying new you should be taking maximum advantage of this market and anything "quoted" by a builder should be immediately dismissed. median prices in Fieldstone and the surrounding area are not that high - and the market continues to settle (nice for decline).
I'm happy to work up a game plan for you and tear into the data, drop me an email or call.
Hank Miller, SRA, ABR
Associate Broker & Certified Appraiser
Prudential GA Realty
Or call / email and I will create a CMA Report for you!