Fair price per foot to remodel or add square footage in Phoenix

[Dirk Gesink]

My wife and I have a 1500 sf property in Central Phoenix with permitted plans to add about 500 sf livable plus a new garage.  It also needs a complete upgrade including kitchen, baths, plumbing, electrical, and A/C.  I was under the inpression that I could get the addition done for about $150/sf and the uprgades done for about $50/sf [(addition 500sf x $150/sf = $75K)+( upgrades 1500sf x $50/sf = $75K)=($150K total cost)].  I have 3 bids that have all come in over $200K, one significantly.  We have plenty of wiggle room at $150K but we're pretty tight at $200K, particularly if there are any unforseen expenses which is likely.  Am I being unrealistic or should I get more bids?  Any thoughts would be appreciated.  Thank you.