Cheers for the response. 

I think it's fair for them to make predictions on revenue, for customers they've had an ongoing relationship with.  Existing customers will have a greater understanding of the potential volumes.  But not with new customers, that perthaps haven't indentified the opportunities or given some indication of committment. 

That said, i'm not well versed in supply chains or how these relationships develope. So i'll just say i'm happy with $1billion as a starting point.