Identify the applicable transaction price
Establish which list applies to the customer, product and period. Today's price may differ from the one applicable to an earlier order.
Where data comes from several sources, identify the version clearly. Applying a current price to historical sales can change the calculation's meaning without producing an arithmetic error.
Sequence follows the agreed terms
If discounts apply sequentially, each later base depends on an earlier operation. Do not automatically add percentages or assume an individual price is merely another name for the first reduction.
A short worked example agreed before launch should show starting price, condition and result so another person can reproduce it.
Retain exceptions and validity periods
A customer-specific exception needs scope and dates. An email held by one person may not reach the settlement team.
For accounting and analytics, the important result is a reproducible base. Trade Marketing connects prices and commercial terms, but needs explicit rules. A price discrepancy can then be discussed against a specific agreement rather than competing spreadsheet versions.