The result really depends on your scene and your system. It’s probably best for you to get your alias to run
_TestZBiasFactor _Less _Enter
and then run it as many times as you need for the scene.
Note that if you run that 4 times, you end up with the factor being \color{green}0.0625 while the \color{green}0.9 you mentioned is almost the same as the default value - which is \color{green}1.