Following are the checkpoints you need to check : 

1. Check whether you have enabled athlete mode or not .  

2. Do not put any wallet , remove watch, extra weight while measuring. 

3. While comparing with previous readings , please consider your water intake .

4. You need to check your body compositions on an empty stomach in the morning. 

5. Do not place your smart scale on a sloped surface. Place it on flat & hard surface. Avoid padding under the scale.

6. Check your profile details i.e Height , DOB . Wrong details will make the difference in body fat. 

7. If you are comparing your readings with an iOS application then confirm the height details before taking measurements. The conversion of Height may cause the difference in body fat.