come out at
1. To leave a particular place to attack someone or something. In this usage, "at" is followed by a person or thing. Keep that door closed because the cat will come out at this bird if it lands.
2. To equal a certain amount. In this usage, "at" is followed by a total or other terms related to numbers or money. My medical bills have come out at such a high number that I don't know how I will pay them.
come out at an amount
and come out to an amountto result in a certain amount, as the result of mathematical computation. The total charges came out at far more than we expected.