Noob question on credit card's cashback signup offer

If I sign up for a 1.5% cashback credit card with a signup promo of $500 cashback with $800 spend in the first month, and I spend $2000 in a single transaction, do I get 1.5% cashback on the $1200 amount above $800? Or is there no cashback for the amount above $800 at all?

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I'm looking at the Standard Chartered Simply Cash credit card. I couldn't find information on this. Anyone know or have experience with such promos?