Discrepancy in square footage

[Josh R.]

I am under contract to purchase a property that I intend to rehab. The local appraisal district has the square footage listed at 1880. I felt like that was off based on how the inside of the property felt. Sure enough when I went and measured every room/closet inside the house I only came up with 1588 sqft.

Without accounting for the footage of the wall space (surely that's not 300 sqft) how could this be off by so much?

Should I approach my seller about this and ask for a price reduction? I was basing my ARV off the footage listed in the CAD.

Edit: MODS please move this thread to the proper forum. I just realized I posted in the wrong one.