I just finished chatting with AMEX online, and I was pleasantly surprised that they lowered my APR on my BCP from 21.99% to 17.24%. My cash advance APR did not change however, from 25.24%. I've had the card for a year and five months.
How often is AMEX usually willing to give an APR reduction? Are they willing to lower the APR on multiple cards at the same time? I have an ED 21.99% that is a year and two months old, and a Delta 19.24% that's a month old. I definitely don't want to spook them in any way by asking for multiple APR reductions or asking too frequently.
I don't know the answer to any of your questions because I'm still fairly new to Amex, but congratulations on the APR reduction!
OP this is already being discussed here: http://ficoforums.myfico.com/t5/Credit-Cards/Amex-APR-reduced-UPDATE-lowered-more/td-p/4087206
Yes, you can request a reduction on multiple cards at the same time. I just did it earlier today.