The Area being Modelled is :-
A Database for Lifecycle of a Sale
William Cody says :-   
Subject: Lifecycle data models
Question: I'm trying to model the lifecycle of a sale as it progresses through various stages like qualification, 
getting a purchase offer, negotiation, and closing. 
Each stage has explicit start & end events, approximate duration, and a set of activities that a salesperson would follow. 
The key element to capture is the progression from one stage to the next. 
Have you modelled that sort of process? 
Thanks.