Years ago I switched to T-Mobile and brought an unlocked Xperia Z3 with me.  I eventually upgraded to a T-Mobile Z3 for the band 12 connectivity.  What I found it that the T-Mobile version would show more bars (4 of 5 I believe) than the unlocked version(1 or 2 of 5).  But when I compared the signals using LTE discover, it had identical signal strength.  Had a similar issue comparing a Z5C to a GS7.  Pretty shady...
				
			
	
	
			
			