Well, from whatever degree of inaccuracy you state, you can calculate an estimated cost to the borrower (or seller) in terms of the likely extra cash he is going to have to come up with on a loan or money they will lose on a sale.
On average across all borrowers, the cost of the error should be zero. But for individual borrowers or sellers, who are concerned about the worst case we can actually come up with a very good estimate of the worst case scenario. For example, you have a 35.75' x 44.75' home. But you measure it at 36 x 45'. That is 20sf over. Around here a lot of homes are adjusted at $600/sf, so that would be $12,000 approximately that the homeowner would have to come up with in cash because of your error.
All is good and well, if we just agree that appraisers pay for their sloppy accuracy. You pay $12K to the buyer and another $12K to the seller - $24K.
You could follow the policy of always rounding down or up and then only have to pay half that or $12K to the buyer or seller, depending on how you do your rounding. Just convince the other party you are not biased.
Oh, by the way, measuring hundredths of a foot - I don't have to pay anything..