Last week, Exane BNP Paribas downgraded shares of BlackBerry (BB 2.84%), citing the fact that its long-term profitability essentially hinges on the longevity of its services revenue, which they believe is unsustainable. In this video, Fool contributor Steve Heller assesses whether BNP is making the right call, by diving deep into BlackBerry's fiscal 2013 results.