Ah, missed that. Still, it's kind of vague, I probably subconsciously read it as "...I could use either one..."...everyone else is assuming it is a requirement, so I'll assume it is, too.
I THINK that it depends on the driver that was written for the card. I see that splitters exist, but it still means that the driver needs to be written such that the correct information is fed to the port for both monitors separately. Still, it'd probably be easiest just to make sure it has two ports, every single computer that I've ever used that had ports could control them separately, be they on the same card or not (or as is standard around my office, has a proprietary port and a breakout cable).