EPRHA is meant to be able to deal with even severely traumatic past and is more focused. AM6 has so many things that your need to process while on it. Like AlphaMind said, the emotional challenges will be more apparent with AM6, especially if you haven't really focused on working on yourself in the past. Using EPRHA first would get most of the garbage out of your way so that the old stuff won't be on your way as much.
Reading your post about stage 3 of AM6, I was in a similar situation. I personally think that since there's so many subjects AM6 touches, without a good founding the first run is bound to be difficult. In your introduction you mentioned that you only did 60 days of EPRHA and didn't leave the sub on "good terms". Not that it didn't help you, but seems to me it wasn't finished. So now AM6 has to deal with that and at the same time program so many new things. On AM6 it should take longer to have the effect that EPRHA would have in a shorter period.
EDIT: forgot to mention that because of the programming of AM6, your point of view will change over time, meaning that some of the stuff will also be resolved because of that not just EPRHA (my own conclusion).
Reading your post about stage 3 of AM6, I was in a similar situation. I personally think that since there's so many subjects AM6 touches, without a good founding the first run is bound to be difficult. In your introduction you mentioned that you only did 60 days of EPRHA and didn't leave the sub on "good terms". Not that it didn't help you, but seems to me it wasn't finished. So now AM6 has to deal with that and at the same time program so many new things. On AM6 it should take longer to have the effect that EPRHA would have in a shorter period.
EDIT: forgot to mention that because of the programming of AM6, your point of view will change over time, meaning that some of the stuff will also be resolved because of that not just EPRHA (my own conclusion).