Over the past 10 days, I traveled from Chicago to Philadelphia and back in Model S. For the most part, the navigation system handled the progression of supercharger stops without issue. Twice, however, I encountered the following glitches: 1. The trip planner had me charge mid-trip at two or more superchargers (all of which I expected to charge at). Sometime after plugging in at a mid-trip supercharger, the iPhone app told me that I had enough charge to continue on the trip. In both instances, I allowed the car to charger even longer, providing a greater buffer. 2. Upon leaving the supercharger, the nav showed my trip as expected - proceeding to the next supercharger. After 5 minutes or so of driving, however, the nav wanted to route me back to supercharger I just left (even though it originally told me I had enough charge to continue and I charged beyond that). Looking at the kWh consumption and traffic, I could see no expected reason why it would want me to reroute back to the supercharger. 3. Despite the nav wanting me to reroute back, I continued on to the next supercharger, and the nav continued to tell me to reroute back to the first supercharger. This direction to reroute even continued beyond the point where the original supercharger it wanted me to return to was further away than the next supercharger on the trip. For example, in one instance, it wanted be to drive more than 50 miles back to an intermediate supercharger rather than continue to the next supercharger only 40 miles away where I was at the time. 4. In both instances, I cancelled the longer trip from the nav and simply put in the next supercharger as my destination and the nav no longer told me to return to the previous supercharger. I don't know if others have encountered this or if anyone has an explanation. From what I can tell from the two instances, it seems to be an issue if the nav determines at any point during the trip that you are to arrive at a supercharger with less than 20% of the battery remaining. Perhaps this is the default "range anxiety setting" so that it tries not to allow you to drop below 20%. Also, although the nav seems to update your progress on a trip by rerouting you backwards, I never encountered a situation after that where it updated itself to say continue on to the original destination when that became closer than the supercharger it wanted me to go back to. In one instance, it projected that I would have 10% of the battery remaining if I returned to a supercharger I had passed, but when I cancelled the longer trip and put in the destination supercharger, it projected that I would arrive with 19% of the battery remaining. Shouldn't the nav be looking at all options to charge and picking the one that is closest?