Clock Plugin
For the most part the criteria points to earn Devil Hunter rank is same for all difficulties except Dante Must Die which is less than Normal.
The requirement for Mission 16 is set to 400 but its actually 1,000 same with Mission 15 its actually 1,400 and Mission 17 is 600 . This was found by bassomegax and tested by Waifu
The grade you get has a lot of factors. Your goal is to clear mission in a short time and optimize usage of your items to not lose certain bonus or a rank. These evaluation points do not apply when you are in intermission (1). Like at the start of game for example. Refer to the mission required times and orbs for the highest points.