Could someone please be so kind as to clarify a craft regulation in HC115.

At 2.5.A.f it states, in F2 and F3, that the calculated or allowed capacity of the lift engine can be doubled if the fan is connected directly to the engine crankshaft.

So assuming the allowed capacity is for a 50 cc 2 stroke, does this mean that one could actually use a 100 cc 2 stroke?