If I remember correctly, the lineage is generally this:
AP400 -> APX400(old) -> APX400(new [post 2002 or 5?])
With APX400(new) being the most hated. If this was modeled after APX400(old) then that's even more cool.
And yes DF, I was mainly referencing APX100 as that's what I prefer, but APX400 is not a total POS film or anything.