Currency mixing pitfalls
Tantalum is priced in USD, but you collect RWF. Here's how the totals reconcile.
Every Tantalum calculation produces two totals: one in USD (the international quote) and one in RWF (the local cash equivalent at today's exchange rate). The 'Total charge' field combines RWF-denominated fees with the USD net amount converted at the saved rate.
Lock the exchange rate at the moment of saving - if the rate changes overnight, your saved calculation reflects the rate you agreed at, not today's.
When sending the calculation to a counterparty, prefer the PDF report: it includes both currencies and the rate used, removing ambiguity.