Most of the time I see the 4G symbol, but it is grey ( rarely is it in color, what does the color/grey mean?) with either no bars or sometimes 1 bar. Then the other half of the time it is in the 1x symbol with maybe 1 bar? Why does it constantly do this, I'm in a 4G speed full coverage area (Orlando,Fl). Can someone explain what this means? Please and thank you!