Pricelists reduce the price on the Sales Order.

Any Customer Invoice will only reflect the reduced price.

The information you are looking for (what discounts have been applied) is on the Sales Order report.

Discounts entered on the Customer Invoice line also reduce the price.

If you are looking for discounts to be represented in Accounting, you would need to either:

•  add a discount line with the relevant income/contra income account and a negative price on the Sales Order or Customer Invoice.
• generate a Customer Credit Note for the discount.