interpolate to nth control point

[appropriate_ladder]

I have a spline with a number of control points.  I can go from one control point to an adjacent control point via Interpolate(% progress, worldSpace).  Works fine. 

My initial take on going from CP0 => CP3 was getting CP3 control point & calling Interpolate from that CP.  What am I missing here?  Thanks. 

Code:

    
  var nextControlPoint = Spline.ControlPointsList[_icp+3];
  transform.position = nextControlPoint.Interpolate(percentCompletion, Space.World);