Let's just take a handful of houses in the area............look a the original sale price (with site premiums included) and today's estimated value. Zillow estimated values are not 100%, but are good enough for gov't work.
#1 $200k, now $518k
#2 $269k, now $614k
#3 $217k, now $542k
#4 $500k, now $734k
#5 $255k, now $511k
#6 $204k, now $531k
They haven't sold yet, but I don't think anyone will lose their $5k or $15k paid premium.