Is there any laptop that seriously uses an adapter with AC output? Why waste space and weight doing AC/DC conversion inside the laptop? All the internal components run off of various levels of DC (so there are DC-DC step-down converters), and you want DC to charge the battery anyway. Desktop computer ATX / BTX / whatever spec are all DC power.
If you're getting (buying) a new AC adapter, you may as well spend a few dollars extra on the beefed-up part, WA16-1000:
That's way overkill, but default WAU12-200 is a bit marginal if charging the batteries and running high power outputs. It's probably plenty okay for most uses, which is why it's default, but it's just to save a few bucks.