You could add all your on text's into one:

on *:TEXT:*:#: {
  if (.av == $strip($1)) && (on == $strip($2)) {
  if ($nick isop $chan || $nick ishop $chan || $address($nick,2) == $address($me,2)) {
    set %Av [ $+ [ $chan ] ] on
    msg $chan Autovoice is on for $chan 
    }
  }
  if (.av == $strip($1)) && (off == $strip($2)) {
  if (%Av [ $+ [ $chan ] ] == on) {
    if ($nick isop $chan || $nick ishop $chan || $address($nick,2) == $address($me,2)) {
      unset %Av [ $+ [ $chan ] ]
      msg $chan Autovoice is off for $chan
    }
  }
  if (.av == $strip($1)) {
  if (%av [ $+ [ $chan ] ] == on) {
    if ($nick isop $chan || $nick ishop $chan || $address($nick,2) == $address($me,2)) {
      set %Auv [ $+ [ $address($2,2) ] ] $address($2,2) 
      msg $chan $address($2,2) added to autovoice list.
    }
  }
  if (.deav == $strip($1)) {
  if (%av [ $+ [ $chan ] ] == on) { 
    if ($nick isop $chan || $nick ishop $chan || $address($nick,2) == $address($me,2)) {
      unset %Auv [ $+ [ $address($2,2) ] ] $address($2,2)
      msg $chan $address($2,2) removed from autovoice list   
    }
  }
}