Yeah, I saw that too. And I would read it the same way, but it is not as clear and authoritative as I would like.

The thing that makes me think that the Altima does have an Atkinson cycle engine is that both the Altima and the Camry have similar "tuning" differences relative to their conventional 4 cylinder brethren. If the Altima's engine is not retuned to the Atkinson cycle, I don't understand why it is rated at 158hp instead of the 175hp of the baseline Altima.

Of course, just because I don't know what else they might have done, that doesn't mean that my guess is correct. Nissan's website is remarkably mum on such technical details.