The output numerical value of differential production is added to {HEAD ~ the current production rate} of the plants to obtain {TAIL ~ a new production rate} which is applied during the forecast period 
to obtain
The output numerical value of differential production is added to { HEAD ~ the current production rate } of the plants to obtain { TAIL ~ a new production rate } which is applied during the forecast period
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH