It does seem overly complicated,call 1 a license and the other registration to simplify.What I did when I bought recently ,and I know others have done the same,is have the seller give me 3 bill of sales.One for the boat,one for the trailer and one for the motor.B.C takes care of the trailer tax when you register it,The boat bill of sale is sent to Transport Canada with the form that I printed off the TC website and they'll tax me on that eventually,If they question the value of the boat I'll add the motor value and pay the tax.Not trying to get away with something but I'm taxed to death already and it avoids paying tax twice on the same unit.