How does the logic of how the total sales amount (including tax), i.e. work in a Sales Order?

Could you please explain to me the logic of how the total sales amount (including tax), i.e. the foreigntotal value of SalesOrder is calculated?

My understanding is as follows

(Item A unit price excluding tax * quantity purchased) * (1 + consumption tax rate)

(Item B unit price excluding tax * quantity purchased) * (1 + consumption tax rate)

(Product C unit price excluding tax * quantity purchased) * (1 + consumption tax rate)

Coupon discount amount (excluding tax) * (1 + consumption tax rate) * value is -.

Point discount amount (excluding tax) * (1 + consumption tax rate) * value will be -.

Shipping cost (excl. tax) * (1 + consumption tax rate)

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= total amount (foreintotal)

I am thinking that the system is to calculate the amount including tax for each item line and add them together to use as the total accounting amount, is this correct?