{TAIL ~ The largest distance} of any focus point from the best fit surface is then identified and compared to {HEAD ~ a predetermined maximum distance value} 
{ TAIL ~ The largest distance } of any focus point from the best fit surface is then identified and compared to { HEAD ~ a predetermined maximum distance value }
TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD