Tracking Status Of Open Work

I currently use a spreadsheet to track my work and I would like help automating some of the functions. I don't want to use macros if at all possible. I have some formulas but it doesn't do enough.
what i do is audit other peoples work and send out error notifications when needed. i use the spreadsheet to help me tack the status of the error notifications. when I send out an error notification the auditee has up to 3 chances to rebut the error so i need to keep track of where the follow up lies and when the error is finally accepted or removed (process completed).

I would like column U to tell me where we are in the process...
1.notification sent (by the auditor)
2.reply received (either accepted or 1st level removal request by the auditee)
3a. if error accepted- process complete
3b. if removal request-notifcation sent(by the auditor - error removed or error remains)
4.if still an error(following 3b) - reply received (either accepted or 2nd level removal request by the auditee)
5a. if error accepted- process complete
5b. notification sent (by the 2nd level reviewer - either error removed or error remains)
6.if still an error(following 5b) - reply received (either accepted or 3rd level removal request by the auditee)
7a. if error accepted- process complete
7b. notification sent (by the 3rd level reviewer - either error removed or error remains) & process complete (3rd reviewer decision is final)

I would like the V column to be the "date of last action"
since the notification bounces between people, i need to know who is currently responsible for followup & how long they've been sitting on the work. i would like the date to populate based on the manually inputed fields where I input sent & received dates for each level of action.

the spreadsheet is too wide for the post so i will put it on a website...
http://public.box.net/kingerick89367

the columns are all titled and all manually inputed except for column U which is the one that I want to autopopulate with the current status of the error notification. the formula is a IF statement but due to the 7 formula limitation It came out too simple. it's better than nothing but I want it to be more specific.