Guide Curves on the Same Plane

Let me say for a Loft guide curves (GC) are on same plane. Two ways you can have these type of guide curves:

 

-All the GC’s are on the same sketch.    

-Each GC is independent of each other.

 

Sometimes 1st one works other times 2nd one works. How to decide that which is the better option? I decided so far by trial and error method.    

SolidworksParts And Features