my first thought was, "expansion? ok, maybe he's talking about stretching the tube, not machining." not that this is obviously preferable, or even possible...but then i googled to find out what exactly those fancy words meant:

"Expansion reamers are used in high-production runs in abrasive materials. An adjusting screw expands the reamer diameter so shops can regrind it to original dimension and re-sharpen it to prevent rapid loss of size or finish. Expansion reamers should not be considered as adjustable for producing holes of different sizes."
http://www.cutting-tool.americanmach...bdeee16_1.aspx

apparently, expansion reaming is still cutting? so my second thought is, "nope...still bad advice."