Excel 2007 : Revenue Recognition/Projections

I am working on a project that deals with contracts. We have the following information (and a whole lot more):

- Contract Start Date (when the contract starts)
- Contract End Date (when the contract ends)
- Delivery Date (when we deliver the data; could be same as contract start date or after (for backorders))
- Contract Close Date (when the contract is signed; date we start to recognize revenue)

It's quite complicated. The existing formulas in the attached file has some problems. Some rows have erroneous calculations. Can someone please help me with the formula?

Any insight will be greatly appreciated.