Right now, you've got a 5% non-feature rate. How are your stats on comments? do a lot of your comments get downvoted to being a "bad Comment or reply"? You'd know that was the case if you got a lot of long "time-outs" ("You've been commenting a lot and need to improve your status in the community" type of message if you had)
I'd say that you're not submitting the two a day on a frequent enough basis, and that may be affecting the number of submissions. Two of my friends here don't post often, but one, that has very few posts, only has two submissions a day. She only posts a few times a month, lately, but she's not worried. Trolls try to knock her down, even then, but it doesn't happen. The other, my cousin, hasn't posted in a while. Surprised, because it's been a while since he did. But he's always had the three a day since he qualified. Mind you, it was like his 3rd or 4th post that ended up on page one.