I haven't, mine's only at 29%. "All groups" for N5 says 29%, but I've actually written for 31. It just doesn't count the N3 and N4 that's in there (that I've written for).
The N5 sections seems to have 133 points in total. I guess 33 of them aren't N5. The N1 section has a few N5 points that are also in the N5 section.
Maybe go through the other sections with CTRL+F for "JLPT N5" and see if you're not missing some there?
You can also try searching for "Written?: 100%" in the N5 section to see if you've missed anything.
Edit: Found one in the N4 section that's N5 and you haven't written for: など, なんて, なんか
Update: I wrote for that one, but it didn't seem to count for N5...