I have doubts about that assumption, but the sample sizes on the wiki for beginner and standard are way too small. DMM users tended to test expert and ultimate more. That said, you'll need to beat 4 copper chests per 10 ap to outdo Expert and 5 copper chests per 10 ap to outdo Ultimate (samples were closer to 5.5, but I'm rounding it down to err on the side of you being slightly less lucky than the DMM users).