Your math makes sense. I have not investigated it to this detail however I have taken a few brisket catering jobs and figured it based on a 50% yield. I weighed the unused brisket and figured based on the left overs that guests were taking an average of 6.25oz from the buffet when the average pork take is around 4 to 4.5oz.
I'd say based on your calculations guest are not taking as much as I thought and I'm loosing the 6% on my expected yield. Thanks Big Mista I'll check in to this further and adjust as needed.
FEC 120, Lang 84, Custom Off Set