On your NAS, go the the DLNA setup. My Seagate NAS allows me to select how often the DLNA updates. My was set for once per day (minimum setting), therefore I had the same problems you did, when I added or deleted files I wouldn't see the changes on my TV. I then changed my setting to every 5 minutes (maximum setting), bingo that did it. I don't the impact of doing it so often, so I changed it to every 4 hours now knowing how the system works. With all that said ... I do believe the LG WebOS Smart TV setting also has something to do with it, I just haven't figured that out yet.
