formula help

I have a spreadsheet that someone has put together long time ago with formulas. I need some more addition to that.First column has employee name, dates the y worked, shift they worked, and hours they worked. *
Column F “Days Count” counting the working days before their day off. For example, Sean Smith – begin work date is 5/16/12 and end date is 5/17/12 so that’s 2 days then he was off 18[SUP]th[/SUP] thru 20[SUP]th[/SUP] so the counting start again from beginning from 5/21/12.

In addition to this what I want is…
I want to count their “days off” as well with following conditions….

1. I need a formula that’s count their days off to see whenever an employee works 4 or more night shifts he/she should have minimum 48hours (2days) off before the next working day. Note: Column C is telling when someone has worked Night shifts. U2 and UF stand for Night Shifts. Blank cells means day shifts.
2. I need a formula that’s count their days off to see whenever an employee works greater than 7 days or nights (>84 hours), he/she should be off for minimum next 48 hours (2 days) before starting the work again.
3. I need a formula that’s count their days off to see whenever an employee works 14 days or nights, he/she should be off for minimum next 36 hours (day and a half) before starting the work again.

I need a formula that’s count their days off to see whenever an employee works 7 days or nights, he/she should be off for minimum next 36 hours (if more than 36 then that’s fine too) before starting again