Originally Posted by
eajusa
...no bonus points in categories that already receive bonus points,.
That is not the way I read the rule:
You will not earn 2X rewards (i) on any bonus you may already receive with your Card, including any additional points/miles/cash back that you may already receive when you spend on certain types of purchases or at certain merchants or (ii) on any other bonus/rewards you may earn with a different promotion or offer from American Express.
I think this means that the Shop Small promotion will add one extra point per dollar, but it will not "double" the total amount earn by the card's category bonus feature.