Problem with gain in AD4111.

I have a problem with AD4111. After reset on VIN0-VIN1 I always read from DataRegister value with gain about 0,423, for example Vin=10V Vadc = 4,23V. The same situation is in unipolar and bipolar mode. My question is -  is it possible that this gain value is normal and I must calibrate it? This is a very large gain change to get a right value and in my opinion something is wrong. But what?