going by what s&s k-52's sell for, my thoughts would tend to suspicion that the appraiser will do some minor refurbishing of the piano and try to resell it for $25 k. or possibly more. small cracks in a soundboard are not rare, they often have no adverse affect on the piano, and if there's a possibility of them becoming bigger, they can be mended. there's still plenty of k-52's around including earlier versions, from a century ago and beyond, because they have a robust build (and because owners and dealers can get premium prices for them). if you've played the piano regularly, did you notice any qualitative or quantitative decline in the amplitude or tone of the instrument ? was it maintained regularly, and if so, what does the technician who took care of it have to say about the soundboard crack ? if you have not played nor maintained the piano, the appraiser has the advantage of you, and is it in your interests to take the word of someone who stands to gain by devaluing your property. it's also possible the piano has problems and the appraiser plans to put in $8-10 k. restoring it.