I never had dirty tranny fluid and have always changed the fluid every year or so. I have also used generic dexron, Castrol Syntec ATF( before fiasco) , Semi Synthtetic, and tech2000 synthetic. The Honda ATFZ1 produces, smoother shifts and is incredibly much quieter than all of the others. I have only flushed twice with it and each flush produces better results. The third flush would complete the process and that is coming at the end of the summer. I bet it gets better yet. My tranny shifts better now than when I got the car 3 years old.
Stick with the ATFZ1 and forget all the other stuff.
BTW, have you flushed your PSF yet? Was your steering real heavy in the cold last winter? Guess what fixed it - and ONLY use Honda PSF.
10 years ago I stayed away from OEM as I thought it was a ripoff, well you learn a few things.