That is sort of correct.
The clearance is for tool clearance, so if you set in 1" for x start and .5 for x finish, and lets say 0 for z start and -1" for z end. say .005 for rough cut and .01 for clearance, and finish cut of .002
The first move will go to z start +.01 and x start +.01, this will be a rapid move.
Then it will move in to x - rough cut, or .995
then it will move z to z end - finish cut or - .998
then it will move x to x start - rough cut and z to z end + clearance rapid move.
all the clearance is for is to ensure the tooltip is well clear of the work when doing the rapids back to the start point of your next cut, it will clear the workpiece in both the x & z.
The clearance will not affect the final end cuts or final dimensions, the finish cut will cut it to what ever you put into your z end and x end.
If you go to the downloads section you will find some more turn wizards that I made to do other cuts not found in the standard turn wizards.
I wouldn't hold my breath for the tutorials, they are busy making new program functions.
Arnie