Everything about the new arrival sensors exactly the same as the old presents sensors the plastic case. So you’re going to see the same behavior.
It’s always good to talk to support, because there are a few adjustments they can make. But ultimately they work great for some people, they don’t work at all for other people, they’re in the middle for other people, it’s just completely variable.
There are other strategies that you can try, including two device strategies. I use an iBeacon and the arrival sensor and the phone and I’m now very happy with arrival detection. But it took about eight months to get it right.