Modification and addition:
into "Axis 1/2" ans "Axis 2:2" TAB :
In "Enlarge"
Extension of the Line in percentage of original length of the Line.
If the extension is 50% it means that each side is extended with 25% length.
Positive values will enlarge the Axis.
Negative values will start to shrink it.
In "Two Points Axis", "Cylinder(s) Axis", "Planes(s) Axes", "Face Normal" and "Axis=(Axis,Point)"
Extension values can be:
Positive values will enlarge the Axis toward OUTSIDE of the Face Object;
Negative values will enlarge the Axis toward INSIDE of the Face Object.