The MLS listing has six bedrooms, 2 baths, 2100 square feet.
This could be an indication that an addition has been done without permits. 416 square feet (the difference between tax and listing) would be adequate for as many as four small (10 x 10) bedrooms. This bears verifying before submitting an offer.
If you're working with a Realtor(c), ask them to check for permits. If you're not working with a Realtor(c) already, please give me a call and I'll find out for you and be happy to provide representation for you.
Tim Kunze, Realtor(c)