In my case, the answer is a resounding yes. It might actually be even more than that. With the MBP even though its rated at 10 hours, I was never actually able to get that much from it. For regular use (lots of screen time at 70-80% with browsing, emails, videos), I was getting more like 6-8 hours with the MBP. The MBA may not be getting me 12 hours, but it beats what I was getting from the MBP by 2+ hours.