First, I confess to using the Epson "ABW" feature only once, when I first got the 3880 printer over a year ago. But I went back and reviewed Eric Chan's description, plus two others I've bookmarked, and now I think I understand your confusion.
Photoshop does not know about or understand Epson's ABW. What Photoshop thinks is that you should control color management either in Photoshop itself or in the printer driver, but you should not use both. With normal color printing, double profiling is a big mistake and results in garbage.
So, when you tell Photoshop to do the color management, it puts up that warning to "remember to disable the printer's color management." That is just a generic warning. Photoshop has no knowledge of what printer you are using so it does not know how "disable color management" might appear in your printer's control dialogue. It's unlikely that those exact words appear in any printer's dialogue.
In the Epson driver, you would disable color management by setting the mode to "custom" and then selecting "off" in the drop-down menu. On a Canon or HP printer, I'm sure it's quite different.
However, when using the Epson ABW feature, you actually do configure both Photoshop and the printer driver to do color management. That's counter-intuitive to normal color printing. But when doing ABW, the Photoshop part of the color management work only prepares the image data for the ABW function of the Epson Driver. That's what Eric's profiles do. Those who do not use Eric's profiles are instructed to set sRGB as the profile in the Photoshop color management dialogue (instead of the Epson profile for the paper being used).
Here are two other sources about ABW that help explain this:http://www.ronmartblog.com/2010/08/how-to-using-epsons-advanced-b-photo.htmlhttp://gerryeskinstudio.com/ABW_sept08_paper/index.html