Not accurate. the raycast happens all along the path. Ignoring it amounts to ignoring the prevNode everywhere. One might as well remove it from the getCost, etc. 
The cost of passing it in is minimal it in really, and with the addition of the new Raycast function to the API the number of variables is "nice" again. 
BTW, with the new fucntion I returned the existing raycast function to its original form and it just calls the other one.