Question about my wifi connection

[Che Castro]

I'm getting good speeds but the wifi bars on my phone are always low 3 or 4 bars never 5
My iPad always has 5 bars still on iOS 5.1.1

Here's a screenshot of my iPhone results
I have an AirPort Extreme ,


I get about 50mb download on my computer
Is this a bug on iOS 6

 

[Che Castro]

Forgot to add that I'm using 5GHz but I never get 5 bars on 2.4 either