Purchased a 2016 LX570 (120k miles) late last year. Have enjoyed it so far with only one minor issue now resolved (Mark Levinson amp went bad). One thing we have noticed is that the AC is not very responsive. When it is hot, we don't see much response until we really lower the temperature and then it takes quite a few minutes. It seems that it does respond quicker when we are on the highway and cruising vs stop and go driving. I had thought initially that perhaps this was related to RPMs. Now I am not so sure. Could it be just low refrigerant?