what Jethro_ meant by saying "Why do you use many checks for op and halfop?"
is you have

if ($nick isop $chan) || ($nick ishop $chan) {

everywhere when you could have done one or maybe two seeing how you have the code

and instead of doing the check like this

if ($nick isop $chan) || ($nick ishop $chan) {

you could do it like this

if ($nick(#,$nick,oh)) {

but whatever to each their own......