Many thanks for your answers. They make a lot of sense to me. As for the 2nd question, i was asking because I had no idea when to ask. I think i have read what you said before, on this very website. But i didn't understand when the appropriate time is to ask your teacher for instruction on these other stances.
I guess I'll just have to ask, because it will be my teacher who knows when I'm ready to learn new things. So if I just let him know that I am interested he will probably tell me when I can learn those other stances.
Kendo-Guide.Com: Thanks for your reply and you're welcome! Yes, asking your teacher is the best solution. But if you hesitate to ask your own teacher, you can ask here anytime. Good luck!