The controller shifts available {TAIL ~ power} between the first lighting source and {HEAD ~ the second lighting source} 
The controller shifts available { TAIL ~ power } between the first lighting source and { HEAD ~ the second lighting source }
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD