it is more a concerning rather a new idea.
I noticed that the Waze change the destination time by one minute without telling me. just changing it, although it is useful that I will know the exact time I wall arrive I think this way of adding the minute to the time "secretly" can cause problems. my main concern is that when I see that the time went up by one minute I feel like I am driving too slow which can cause me to speed up. maybe you can change the way you adapt the time to the destination like you do when you see traffic is beginning to create later in the road. just a notification that said the traffic made the change rather a slow speed which can cause more speeding on the road. you can easily check my concern with your data, hopefully, I am wrong