Do Not Disturb While Driving and still strange auto lock behavior

Hi everyone,

Can someone please address these two issues?

1. I asked about this a couple weeks ago, and all I got was that it might be an issue with notifications, but I don't think it is as I updated to the latest operating system. Here's the issue, it seems that when auto lock is set to anything more than 30 seconds and the home screen is displayed with no apps running, the screen seems to lock in half the set time. For example, I have my phone set to auto lock after 5 minutes, but it's consistently locking after only about 2 and a half. Is this a bug? If not, how do I fix this?

2. I am a frequent user of both Uber and Lyft, and many times when I'm in the car, I let my phone lock during the ride, as I don't use it unless I have to take care of some things while on the way to where I'm going. Since getting the new phone and upgrading to iOS 11, every time I'm in an Uber or Lyft vehicle, I get a notification about do not disturb while driving. As I am never going to be the one driving, how do I permanently disable this notification? Do Not Disturb while driving is set to manual activation, so it's not actually being activated. However, I already know about the feature and as I don't drive, I don't need it, and don't want to be notified about it when my phone thinks I might need it.