In physical commodity trading, P&L is calculated deal by deal: sale price minus purchase price minus every cost line attached to it (freight, commissions, certificates, port charges, bank fees, insurance and, where applicable, claim reserves).
At an aggregate level, monthly or quarterly P&L adds up the individual results of the deals closed in the period and subtracts the team’s fixed costs.
Running P&L in a spreadsheet works with a handful of deals, but past 10-20 operations a month the same errors keep appearing: broken formulas, forgotten cost lines, inconsistent exchange rates. A CTRM computes it straight from the deal inputs.