Since there's no defined criteria and it seems to wildly vary I don't think chasing CK status is worth it. The service can be hit or miss, often miss. I really do not need a text telling me my flight is on time or even late. I text telling me what's going on, for example why is the incoming flight being shown as Awaiting Takeoff for one hour now. But agents may not have specifics. I haven't had a close connection yet where a cart or car would have been required.