Long-tail cast on: slip knot required?

[chixdilla]

I am reading an article on the Craft Yarn Council website that says that when casting on, you must always first make a slip knot, and that slip knots always count as a stitch. For example, if a pattern calls for casting on 12 stitches, you first make a slip knot, then cast on 11 more stitches. I like to cast on using the long-tail method I learned on this site, which never specified making a slip knot. If I use this method, do I still have to make a slip knot before beginning the cast-on?