This website pulls information from public records. If the owners have expanded, with or without permit, regardless of what it shows on the appraisal, as long as the owners have not gone to submit the change to public records, the records will not be revised to reflect what's there.
That's why it's challenging to use public records because too often, the public records and the what's actually there don't match.
Some owners have made revisions to their property --- added rooms, baths, etc. Even if it's done with permits, they assume that the expansion will be automatically reflected on public records. Not so.
Some owners deliberately withhold the information about the expansion because they're afraid they will be taxed more.
Some owners merely or innocently forget to submit the change.
If one applies for the change in the records, a county appraiser will be dispatched to review the expansion, take measurements, determine if the work was done with permits....and if approved, the expansion will be noted and the public records will change accordingly.