uniball™ Signo RT, Gel Pen

The 0.7, but by any other name..

I'm sure the Signo RT is a fine pen, and it says 0.7, but it writes a fatter line than my uniball Signo 0.7 stick pen (non-retractable). Too bad, so sad, that they're discontinued. I can't find another pen like it. I don't understand why two 0.7 pens write different widths.