Got an email from American Express about enrolling to get 2 extra points per $1 spent. Have to enrol by 2nd November and the bonus period applies for purchases made between 15th November to the 15th February 2018. As per nightelves comment for Amex credit offers the total pre credit would apply. eg Spend $50, get $10 credit. Bonus points applies for the $50.
Note Have only linked the main Amex website - you will need to check your email as it looked like the link is associated with your Amex account. Unsure if this applies to bank-issued Amex cards - please let us know if you received the offer for those cards too. Thanks!
Points would be applied for the $50 spend.