LOL Touche, good Sir! :new_2gunsfiring_v1:
Not unsupported - the county appraiser is pretty consistent - just not always accurate. When a builder presents a model floor plan and tells the county he's building that house on this lot and that lot, the county looks at the plans and determines what the GLA is. Then assigns that figure for GLA all of those homes. So if the person who calculates the GLA (be it the builder or county employee) gets it wrong, it's wrong for each of those models.
So if I've confirmed the GLA error for one of those models, it's not unreasonable to assume it's the same for each of those models in that phase of the development, particularly if the error isn't huge. Outside of that model and in that development, I have no reasonable basis to defend or asail the county's figures (outside of a conflict with MLS info, and then I have to query the listing agent if he/she can be reached).
Effects of relative humidity upon our central nervous system aside, we have to make a lot of assumptions and other judgment calls in every appraisal we do. Unless an involved party or listing report tells me there were problems with the condition of the comparable, we assume it was in average condition at the time of sale with no need for repair - but we don't know for sure, because we haven't been inside the comparable.
As I said earlier, our responsibility in making those assumptions or judgment calls is to disclose and issue caveat lector.
Le me ask you this: in your scenario, subject shows 2,500, you measure 2,300. What do you use for GLA and what do you show in your sketch? Do you fudge your sketch to make it match PR, or do you use PR numbers but show a sketch that doesn't match? If you use your own number, do you then make adjustments to homes you feel reasonable certain have 2,300 real SF, but for which PR shows 2,500?
To me, these types of situations demand we make a call - we can be wrong, as long as we warn the reader that we are not totally sure and layout the logic for our call. Fortunately, most of the times I've run into this situation, the numbers have either been small (due to rounding errors) do it's been more than reasonable to assume all models reporting the same SF are in reality what I measured, or it's come to light that a change to the plans were made after the original permit was pulled and the county failed to update - and the homeowner isn't going to tell the county their house needs to be assessed more for the extra GLA
