No, he didn't really lie.  He just left out some information, like the fact
that the misfire when the cleaning agent ran out actually caused the lamp
to come on, that a proper and complete job would have included checking
the codes and erasing them if appropriate when done, and that they don't
have a tool to read and erase the codes.  The lamp probably will go out in
a couple days as the system detects no more misfiring and decides
everything's okay.  The code will remain in the computer for quite some
time, however.  It's a good thing the emissions test was done first,
otherwise, you'd be really irate right now.