how to apply Qty count by separate formatting to multiple different Excel table columns?

i would like to do a Barcode scan on product with Qty count in excel as show in Row E "Qty Count By Barcode Scan" and the product code will appear at ROW F "Product Scan". Whatever i scan is only mactch and count according to the customer, let say when i do scan and count for customer A it only go for customer A and won't go to other cusotmer like customer B or customer C and so on.

the problem i having now is it will go match and count for other customer. let say i doing scan and count for customer A and whatever other customer have the same product code will be counted too. So this is my facing problem.

how to separete it for each customer so it wont in the excel so it wont intterupt each other when doing product scan and count.
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thank you

best regards