Looks like a good use for $reptok.


var %r = $readini(settings.ini,options,user1)
writeini settings.ini $reptok(%r,$gettok(%r,4,124),Off,1,124)


You would most likely use $1 instead of Off.

Here is an example.

Code:
/test On

menu channel {
Turn $iif($gettok($readini(settings.ini,options,user1),4,124) == On,Off,On) :test $iif($v1 == On,Off,On)
}

alias test {
var %r = $readini(settings.ini,options,user1)
writeini settings.ini $reptok(%r,$gettok(%r,4,124),$1,1,124)
}