I think technique is a major factor...take it from one dummie that found out the hard way...
On harder heads, I was bearing down harder with the older diamond stones... the knife jaws had a bit thicker rubber grabber then the newer BH jaws.
The result was the head would move slightly due to MY downward pressure and I wasn't getting a consistent stroke.
I like how Ron and his Bro have updated the varied jaws to help those of us with flawed techniques improve outcome. If you let the stones do the work, as it's supposed to, I think you'll be fine. Some years back I was in the enviable position to get both the knife and BH sharpener so I just use the BH Sharpener and consequently, I didn't get the newer bh jaws...but I see their design would have improved my efforts greatly!
All I've done in recent years was update my stones/diamond slabs as better ones came available from Ron...