I used a cost of living calculator[1] and compared it to theirs. Found the numbers don't match up. Just matched Nashville vs SF and the low end of Nashville was higher than the low end of SF (-3000 SF dollars) but the high end of Nashville was lower than the high end of SF (+3000 SF dollars).

[1] I've found this calculator to be decently accurate http://www.bankrate.com/calculators/savings/moving-cost-of-l...