I am sceptical of Apple's battery figures these days, sadly.
They used to be conservative; the first two years of the iPad had battery life figures of 10 hours for browsing the internet on wifi, yet they easily outmatched that by one or two hours. In contrast, my iPad Air 2 has the same 10 hour quoted battery life, but I find in reality that it is more like 8 to 9 hours.
It's the same with the laptops: the first two generations of the MacBook Air had great battery life, but in recent years, they have stagnated or got worse. Battery technology is the ugly duckling of modern devices. It's the one significant area where we have had no real improvement for decades.
They used to be conservative; the first two years of the iPad had battery life figures of 10 hours for browsing the internet on wifi, yet they easily outmatched that by one or two hours. In contrast, my iPad Air 2 has the same 10 hour quoted battery life, but I find in reality that it is more like 8 to 9 hours.
It's the same with the laptops: the first two generations of the MacBook Air had great battery life, but in recent years, they have stagnated or got worse. Battery technology is the ugly duckling of modern devices. It's the one significant area where we have had no real improvement for decades.