> .ds { \v'-.9m\s'\En[.s]*7u/10u'+.7m'Wow. I didn't know that was possible. You're interrupting the calculation of the amount of vertical movement to set the point size, and then use the new value (as ems) in the interrupted calculation... But the result is correct, it's equivalent to \v'-0.41m'\s'\n[.s]*7/10' where -0.41 = -0.9 + 0.7*7./10.
