else {
if (%autologin == off) { }
}
is an unneeded line. since you have the if %autologin == on it won't do anything if it's off.
you could get rid of that line all together the if statement by using groups such as

autologin off

on *:connect: {
msg nickserv identify
}

autologin end

then in your on text event change
on :text:!autologin :#:{
if ($2 == on) || ($read(owners.txt, s, $nick) != $null) { {
set %autologin on
msg $chan $nick toggled my auto identify mode ON !
}
else {
if ($2 == off) {
set %autologin off
msg $chan $nick toggled ny auto identify mode OFF !
}
}
to
on :text:!autologin :#:{
if ($2 == on) || ($read(owners.txt, s, $nick) != $null) { {
.enable #autologin
msg $chan $nick toggled my auto identify mode ON !
}
else {
if ($2 == off) {
.disable #autologin
msg $chan $nick toggled ny auto identify mode OFF !
}
}