mobile

Hi I bought the N910C for At&t, after doing some research online I know that asu is usually dbm+140. It is accurate on my old GS4 it getting -100dbm 40asu. On the other hand my note 4 is getting weird numbers like -101dbm 6asu and the difference is 95 and not constant.
I am worried if I got a defect phone or it how N910C works on antenna formulas. Please help I am debating whether should I return the phone...:(
thanks