If you got AMEX Gold Credit Card, you are rewarded with Membership Reward Points. With MR points you no need to redeem for voucher as you can redeem for cash back i.e. 200MR points = RM1 cash back or that's equivalent to exactly 2.5% cash back with 5X MR for petrol. So with AMEX Gold CC, do not redeem for vouchers, instead redeem for cash back. This is  because when you use voucher which you redeem, you wont get new points 2X or 5X with your AMEX if you were to use the AMEX Card to purchase the same thing you would with the voucher. Get what I mean? 

The voucher equivalent of 2.5% is applicable to Maybankard 2 AMEX only. Seriously, if you have AMEX Gold CC, I sugesst you switch to Maybankard 2 Cards and use the Maybankard 2 AMEX to get 5X Treats Points and best of all, 5% cash back on weekends.