no need for two diff events as well no need for global vars.
just one of the many ways to go about this, but auto talkers are annoying and prob will end up getting you banned from channels.

#thank off
On !*:rawmode:#: { 
  if ($regex($1,/\+[vo]/) && $2 = $me) {
    msg # Thanks For The :( $replace($1,+o,OP,+v,Voice) ): :( $nick ):  
  }
}
#thank end
menu status,channel,menubar {
  .Turn Auto Thanker $iif($group(#thank) = on,Off,On):{
    $+(.,$iif($group(#thank) = on,dis,en),able) #thank
    echo -a AutoThanks Is Now $group(#thank)
  }
}