Because people change over time their dream signs also change. I think it would indicate some sort of problem if they never changed! Because of this it is a good idea to update your dream signs from time to time. I know some of mine are fairly stable -- Christmas time and a certain group of friends, but the rest come and go. When I write in my DJ I keep a hilighter pen with me so I can mark anything that pops out over and over. I also go back and re-read my DJ so I can catch any emerging dream signs.

The mantra part of LD induction works surprisingly well for most people. A big part of making it work for you is finding a mantra that makes sense to you. I personally like "I realize when I'm dreaming." It isn't necessary to keep repeating the mantra up until the moment you fall asleep. I usually only repeat it until I start having a hard time hanging on to it because my mind is drifting randomly. For me the random thoughts stage is a big indicator that I'm about to fall asleep.

It sounds like you are doing everything pretty well. Perhaps you should update your dream signs and experiment to find a mantra that works the best for you.

Good luck!