The whole "flip it" comment is a bit of a forum joke realy so it shouldn't be taken too seriously. Useful if you realy wan't to lower the stem but this asumes that the stem is angled upwards to begin with. The other thing you can do is take some of the spacers out from under the stem and fit them above the stem to lower your handlebars further and you can play around with combinations of spacers and stem angle. You can't remove the spacers however unless you go the trouble of cutting down the steerer but they work perfectly fine on top of the stem.

Regards, Anthony