in step {HEAD ~ the first cooktop unit} is preassembled with {TAIL ~ one cooking system type} and the second cooktop unit is preassembled with a different cooking system type prior to mounting on the base units 
is preassembled with
in step { HEAD ~ the first cooktop unit } is preassembled with { TAIL ~ one cooking system type } and the second cooktop unit is preassembled with a different cooking system type prior to mounting on the base units
OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH