It's pretty clear that Apple Inc.(NASDAQ:AAPL)'s bewildering post-earnings 14% sell-off wasn't caused by the previous quarter. Apple reported relatively in-line with expectations, even posting some upside to expected earnings. Instead, all focus was on next quarter's guidance.

The company called for $41 billion to $43 billion in sales next quarter while analysts had been expecting a total closer to $46 billion. In and of itself, that kind of light guidance is forgivable. Apple Inc.(NASDAQ:AAPL) is notorious for lowballing and easily beating guidance. As an example, in the previous quarter, Apple had guided to $52 billion in sales before ultimately posting $54.5 billion.

Instead, what spooked investors was on the earnings call, when CFO Peter Oppenheimer repeatedly insisted Apple was changing the way it gives guidance. Instead of giving a "conservative" estimate that Apple had "reasonable confidence in achieving," the company's newest guidance is given in a range of what Apple is "likely to achieve."

Huh? This might all sound like mere semantics, but it left the market truly befuddled. After lowballing guidance for years, Apple Inc.(NASDAQ:AAPL) suddenly seemed very firm that investors "take their word" on their guidance. That's a huge change from how past Apple guidance was analyzed. Rapid change creates uncertainty, and uncertainty is often punished harshly in the markets.

If we take Apple's word on its guidance next quarter, its growth is slowing far more than Wall Street had expected. Over the short term, it leaves the company in a bit of a no-win situation. If Apple Inc.(NASDAQ:AAPL) hits in the range it guided to next quarter, investors may still be disappointed. Even after a series of analysts trimmed their price targets, they still expect Apple to post $43.2 billion in sales next quarter, above its guided range.