[taspeotis]

So you need at least Professional, which is 1/10 the cost of Ultimate. Which puts your percentages closer to 5-10%*

*Based off your claim that a developer is 10 to 20k and assuming USD I converted the prices from here: http://msdn.microsoft.com/pt-br/subscriptions/buy.aspx

Note retail can be cheaper, but you don't get MSDN with it.