How do I increase Green Affix?

I just got a green affix nadroji, and it is currently at 5 right now, is this the max green affix go? Because I try to add +2 all set set mythstone to my jewelries and that didnt do anything?

cap of + set affix is 4.

You can add like 1 more if you use 2 gears of nadroji affix.

nadroji helm
nadroji ring
+2 set affix
+2 set affix

= nadroji (6)

I prefer to use another set affix though than using 2 with the same affix. I just gave a scenario.