The consensus estimate for Apple's (NASDAQ:AAPL) fiscal 2014 second-quarter iPhone shipments is 38 million units. But Morgan Stanley analyst Katy Huberty's AlphaWise survey estimates Apple will sell 42 million iPhones. This 4 million unit difference in estimates shouldn't be ignored -- especially since Huberty's AlphaWise survey has proved to be more accurate than consensus estimates.

Making the matter more intriguing, 4 million additional iPhone sales could push Apple into blowout territory, a place Apple definitely didn't reach in Q1. As Apple's most profitable segment, 4 million incremental iPhone sales could play a big role in Apple's bottom line, helping the company easily post two quarters of EPS growth in a row.

Fool contributor Daniel Sparks takes a closer look at Huberty's estimate, and the implications for investors in the video below.

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