Value of X I think

Hello,
I am dealing with an insurance company. My vehicle had 63,402 when it was totaled. The insurance company has given me 6 comparable vehicles.
Vehicle 1 has 69,653 miles and the insurance company there is a $425 difference due to mileage
Vehicle 2 has 19,320 miles and the insurance company there is a $2,517 difference due to mileage
Vehicle 3 has 64,285 miles and the insurance company there is a $62 difference due to mileage
Vehicle 4 has 48,193 miles and the insurance company there is a $926 difference due to mileage
Vehicle 5 has 59,357 miles and the insurance company there is a $274 difference due to mileage
Vehicle 6 has 54,227 miles and the insurance company there is a $589 difference due to mileage

Can someone tell me what the formula the insurance company is using to determine the dollar value difference due to the mileage difference.

Thanks for your assistance.