Unfortunately the maps and POI in all OEM NAV are several years out of date and unreliable.
In my area there was a Shell station that was removed years ago and it still showed up in both my D and ML Nav.
I rely on the Gasbuddy app on my android phone to give me up to date info on gas/diesel stations when I'm driving. The app also displays the price and address which I can then click on and activate the Google NAV app to guide me to the station closest to me.
Sent from my Nexus 7 using Bimmer App
2013 E350 BlueTec
2011 VW Jetta TDI