Hey all, here is something I want to share with you guys, it's a very simple JavaScript-based HTML app I wrote a few days ago, that I call the "Project Diva F Maximum Failure Calculator".
http://pastebin.com/ZNujUh1R (updated 10/3: fixed colors)
Basically, you enter the total note count of a F or F 2nd song (as seen on the results screen), and whether or not you have passed the Chance Time and the two Technical Zones, and it will compute for you the highest amount of notes you are allowed to fail in order to reach a Standard, Great, or Excellent grade.
This script can be helpful in a situation where you are having trouble finishing a song and wondering by exactly how many notes you're away from a Standard, or in cases where you're working on improving your current grade on a song and want to have an idea of how much you need to improve upon to get a Great or an Excellent.
It's purely client-side driven so it doesn't need to run on a server, you can just download it to your computer and open it directly with your Web browser. (I should probably find a more suitable host than pastebin in the near future)