In my opinion, yes it is possible to beat all the levels of ninja exam with that power. I beat the exam at 63k power

okay wait I think I misunderstood your question haha. If what you're talking about is the amount of time it took them to complete all the levels of ninja exam i.e. 45 days since the server started, then yes it does somehow feel unlikely for it to happen. But I don't know for sure.