According to the ecample "ganfetex02.in : GaN HEMT Breakdown", to resolve breakdown, the voltage contact shall be change to current contact, but as the drain cotact was applied positive voltage, why there is not "ifinal=-1"?

solve vstep=0.1 vfinal=1 name=drain b1=$light solve vstep=1 vfinal=10 name=drain b1=$light solve vstep=2 vfinal=20 name=drain b1=$light solve vstep=5 vfinal=1200 name=drain b1=$light cname=drain compl=0.5 # change to current contact to resolve breakdown contact name=drain current solve solve imult istep=1.1 ifinal=1 name=drain