Dealing with false alarms is so frustrating. I always install mine up high, way fewer problems that way. Totally get why you're doubting the placement.
Ever try putting one lower instead? @pipera50, high is great for steam, but what about a smoldering fire that starts near the floor? I stuck one low in a hallway after my couch had a slow burn from faulty wiring, caught it way faster than the ceiling one. Moisture in the air from bathrooms can mess with any placement though.
High placement actually misses the first critical minutes of a smolder, which matters more than avoiding an occasional false alarm. Stuff on the floor gets bumped or blocked way too often anyway.