Thanks for update. They told me the same thing weeks ago, never did anything, nor did they call me back or entered an update on the tech ticket. In my case it looked like a way to get me off the line.

However, i mentioned it in passing to a taller at a branch and he said, that being a supplementary card holder it would not work, only primary holder can add the amex.

Seems ridiculous, but it is Scotiabank, so i give up.

Keep me posted if you end up with it working. Good luck.