Another factor to consider is the number of stories. Most homes I see 2500+ sq ft are two story, most 1500sq ft homes are one story. The two story home has “dead space” where the staircase is that is of little use, so its effective sq footage is less than measured square footage. So two 2500 sq ft houses, a one story and a two story, the one story will “feel” bigger because it lacks dead space. This leads to higher ppsf for single story homes.
As for your original question, yes. Rich calculates a median ppsf for condos and homes monthly to use as an indicator of future Case Shiller (sp?) changes.