It is my belief that this confusion generally arises from taking house systems out of the context of their time and the particular methods they were each applied to.
For example, in this particular case, Ptolemy in his third book of the Tetrabiblos describes two completely different house divisions when focusing on life and death matters. The difference is the calculation (or perspective) in order to determine the difference between what "rules" life and death in the chart vs. when they actually are "active" and can be "used". So, you see a difference in divisions as to how to first determine what is, as opposed to, when to use what is. Each having a different way to divide the chart to determine these.
I am certainly no scholar and I leave that to greater minds but, there appears to me to be a lost view of perspective as to when to use different house systems for particular reasons. It was not just a free-for-all by any means and there was a method in choosing what has now become madness of choice. lol