API paypal "book" amount in advice

[morp]

Hello everyone,
I have a question .. I basically sell products that are "prepared" at the moment, and they have a cost per kg.

With payment by credit card so I will do this:

When ordering you pay a standard amount (cost per kg + 10% excess margin).
The cost is booked on a credit card, and only then, when the shop operator will cut and weighed the product (food), I will know exactly the real cost. At that time the real cost (the same or less of the amount "booked" before) will climb to the credit card.

All this, as I said, with payment by credit card, via the API that gives me the POS of the payment gateway of the bank ..

Do you think such a thing is possible with Paypal?

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Or maybe can I disable paypal payment method only on some products?

Many thanks
bye