This tilt type is used for generating toolpaths for tube milling, port machining (engine inlets). The tube milling usually is machined in Z-constant cuts and the results are cut slices. The amount of the z constant cuts depends on the maximum step over. Now the tilt curve will be divided with the number of slices of the toolpath. Every slice is now aligned to its point on the curve. Make sure that the beginning on the curve is on the right end.
Click "tilt curve" and select the curve from you geometry. The curve tilt type is "from start to end".
In this example the maximum step over is 10 mm. The toolpath for the tube has 10 slices. So the curve has 10 points. Now every cut is aligned to its point on the curve.
Note that if you use a collision avoidance strategy "Stop toolpath calculation" or "Leaving out gouge points" and this causes the last slices not to be machined, it will look as if in the last cut the spindle is pointing to a point on the curve other than the last one.