MobiKwik is the cheapest for Amex to Bank @1.90%
Load upto 10k at a time using CENTURY coupon code so you get 1% cash back upto 100 per txn (6 txn per day allowed)
So you get charged 10295 for getting wallet balance 10100.
Net cost 1.90% without counting value of approx 200 MR points depending on your card.