The percentage volume increase required to maintain profit, for discounts given.

Giving discounts for volume is a very slippery slope.  Let's imagine a salesperson is with a customer, and that customer demands a price cut - not requests, you understand, but demands, 'Five per cent or there's no order'.  She is, however, an understanding customer, and she knows that the salesperson will want something in return, so offers him some extra business.  The question for the salesperson is:  how much more volume is required if profit is not to go down?

Table:
The percentage volume increase required to maintain profit, for discounts given.  
http://spreadsheets.google.com/pub?key=t2Lxh7iEVIhpXIkhjO4SR0g&output=html