I can't change the target by the same amount because the lowest I can set the machine I currently have is 30%. Except 30% on that is 70%+ in actuality. So that means it will turn on for 75-80%. That's way too high. If it let me turn it to 0% or 5% then that would be fine.
Oh yikes. Then that's definitely not in the "miscalibrated" range, that's just totally broken.
And while humidifiers can suffer from moisture buildup next to the sensor which you can fix in a couple of minutes with a handheld fan, that shouldn't be the case with dehumidifiers.
Sorry but it sounds like you just need to get a new one. Hopefully it's still under warranty. Your unit isn't representative of what's being sold these days, it's just flat-out defective.
(I assumed you were talking about a difference of 15-20 percentage points, which is more common to see, although more in humidifiers than in dehumidifiers.)
