OK, we appraisers can now see that the $8-10K being talked about is the Price Per Square Foot.
Shannon, Realtors and other non-appraisers use the price per SF as a value tool, BUT that skews statistics in reality!!! The only way it makes ANY sense statistically is if ALL properties used to determine the price per SF were all almost identical. That would mean there were no differences in the lots (sites), the style of the house, the quality of the construction, the age, the upgrades, the additional amenities, etc. - ALL ALMOST IDENTICAL.
If you look at the sales comparison grid on an appraisal, you'll see various adjustments taken for various items. All of those other items need to be adjusted for prior to the square footage adjustment, or at least the basic items that are above the center of the grid where the SF adjustment is located.
So, for your property, the actual adjustment for square footage differences is probably closer to around $20 or $40 per SF, DEPENDING ON WHAT THE MARKET DATA FOR A HOUSE LIKE YOURS IN YOUR AREA SHOWS. Shoot, I've seen some where a difference of 100 - 200 SF had no justfiable adjustment for that difference at all. 100 SF adjusted at $30 per would be a $3,000 adjustment.
Now, tell your Realtor to back off. Just because they have a real estate license doesn't mean they know anything at all about appraising or justifiable values of real estate. Your Realtor is NOT a disinterested third party to this transaction. Don't let her/him turn your head with misinformation and skewed statistics.