It doesn't in the sense that they are measuring the square footage the same way. As far as whether a home is more expensive per square footage on a 2 story home....probably. Many people like the idea of a two story home and so they pay more for it. That's just an opinion....each situation is going to be different. Did that make sense?
I give a general answer that 2 story homes are less per sq ft then 1 1/2 story homes & ranch homes are generally the most expensive per sq ft. Sq ft pricing is not usually the best way to compare homes as homes vary greatly in fixtures & quality of construction & materials used. Some people include the cost of the lot in the cost per sq ft and this can greatly skew the data.