Hi Ryan,
Sorry for the late response!!
I completely forgot that I had not followed up on this issue. I modified the settings as you described but have not yet been successful with a call waiting procedure. The situation 'appears' to be improved, however, as I do not lose or drop the call as quickly as before.
I'm currently using and testing this setup on my Obi100 that is using a non-essential line. I will keep testing/trying and let you know if I make any progress in the future. Although my problem is not completely solved, at least you have pointed me in the right direction!
Thanks again for your help
pc44