The processing tool having {HEAD ~ significant utilization history} may be the same processing tool as {TAIL ~ the processing tool} with little or no processing history where a manufacturing event disrupts the operations thereof 
The processing tool having { HEAD ~ significant utilization history } may be the same processing tool as { TAIL ~ the processing tool } with little or no processing history where a manufacturing event disrupts the operations thereof
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH