Since unveiling its first Surface in mid-2012, Microsoft Corporation (NASDAQ:MSFT) has lost at least $1.2 billion trying to help the struggling tablet lineup succeed. To be fair, much of that amount stems from a $900 million writedown Microsoft took for "inventory adjustments" around this time last summer. But Microsoft's total cost of Surface revenue has already exceeded sales by at least the remaining $300 million, including a $45 million loss during its most recent quarter alone.

But according to the Fool's Steve Symington in the following video, those losses might be about to increase even more thanks to a new Surface incentive program aimed at winning over current Apple (NASDAQ:AAPL) loyalists. Specifically, through the end of July, Microsoft is offering up to $650 in store credit to MacBook Air owners willing to "trade up" to a Surface Pro 3 -- a hefty sum considering Microsoft's entry-level Surface Pro 3 starts at just $799.

More likely, Steve says, is that Microsoft is using the incentive to steer Apple's MacBook Air users toward the premium, higher-margin Surface Pro 3 models. But even then, Microsoft could have its work cut out for it persuading a large enough number of Apple loyalists to jump ship. To hear Steve's full take on what this means for both Apple and Microsoft, please watch the following video.