Wes, I gather that you are the homeowner from your statement. As such, it would seem prudent to me that you would have provided the information (survey, plat, etc.) about the lot size to the appraiser. It would seem that once you became aware of the error of the lot size that you would have provided the information to the lender, who is the appraiser's client, so that they could then forward it on to the appraiser. The longer you wait to provide the information, the more the headaches become. Also, after a certain point in time, the appraiser may have the option to decide if this is a new assignment due to changes in information, details and facts that were not presented in the first place. That would be up to him/her to make that decision.
As far as your question:
"the appraiser is stating that he is required to use the lot size as stated by the tax appraisal by the Fannie Mae guidelines. Is this correct?" The appraiser is charged with utilizing sources that he/she deems reliable and accurate. As such, most county tax websites offer information that almost every appraiser considers to be accurate. If you knew this was incorrect before, why didn't you take the steps to correct the accuracy of the information?
There are several locations in the "Appraiser's Certificaiton and Limiting Conditions" that provide clarification to the appraisers' limitations and research. A few are:
1. The appraiser will not be responsible for matters of a legal nature that affect either the property being appraised or the title to it, except for information that he or she became aware of during the research involved in performing this appraisal. The appraiser assumes that the title is good and marketable and will not render any opinions about the title.
13. I obtained the information, estimates, and opinions furnished by other parties and expressed in this appraisal report from reliable sources that I believe to be true and correct.
There is nothing that I'm aware that states the lot size is obtained from a specific source. It just must be obtained from a reliable source and one that an appraiser's peers can verify and/or research as well.
Hope that helps. However, part of the problem does appear to fall back on you if you are aware that the tax web site was incorrect.
