Bluetooth microphone and cruise control issue

[kal]

Hi all

I have a 2011 Audi A7 and find when I set the cruise control, the actual speed it shows I'm doing on the dash is about 4/5 mph slower. So if I set it at 70, the speedo will show I'm doing 65. This is the same at any speed I set it to, always slower than I want.

 

Also, I've noticed my microphone when using my phone can catch a lot of background sound so who ever I'm talking to can't really hear me. I've tried adjusting the settings on MMi but that has not changed anything. 

Any help would be apprecaiated!