Got Barclay Arrival World Mastercard (40,000 bonus miles with $89 annual fee waived) approved for me and my wife. It's our first Barclay card, and we had applied for around 4-6 cards in the last 6 months. Both our scores are over 770. My application was instantly approved, while her application said it was being reviewed, but changed to approved a day later.

Anyway, here's my question. Can I use the card for a single travel expense worth $1000, and then, apply the $400 credit/cash back? That is, I will be paying only $600 or so as my first month's statement. Is that allowed?