My Akarui dry cab's both hygrometers was off by 10% after testing. But it was off on the dry side. So if they show 50%, it is more like 40% actual. They are now both fine after calibration.
So my advice is, test them. So you will know if they are off or not. And by how much. And feel free to calibrate them. The analogue ones are easy to calibrate.