Yeah that electronic controller thing you hold is a joke. I got my bf measured via calipers and it came back between 8.5-9.6%. I increased my cardio from 1 day a week to 4 days a week and slightly reduced my calories for 6 weeks. Afterwards, I got my bf taken again using the thing you hold and it gave me something crazy like 14.5%. I knew it was inaccurate, but nonetheless I wasn't too happy.
The mirror doesn't lie.