Flat rate shipping cost

Hi dear,

I hope you are doing well.
Please, I want your help to configure a type of flat rate for shipping.
I want t set up shipping costs for products, for example:
If someone buys 1 quantity the shipping cost will be $58.80 if they add 1 more to the cart, it will cost them $10.96, which means the total of 2 quantities will be $65.76.
And I want it to apply to each product they add to the cart will cost them $10.96, except the first one will be as it is $58.80.
I used this code 54.80 + ( 10.96 * [qty] ) in the flat rate cost, the problem is this calculated $65.76 in the first quantity.

I hope this is clear to understand.
Best regards.

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