They use 768 BECAUSE it is not in the dial plan - when a call transfers to 768, it actually transfers to the first logical station ID, which is your Operator console. BUT, the call will not be eligible for coverage. Which may not be what you want, so it's perfectly OK to change the CASO to the Operator's extension number, or to the QCC's LDN (you're not really using queue call operators, are you???)