Typed once, in the currency it was quoted in.
Each wedding has its own base currency. A quote in pounds and a deposit in euros are stored as they were typed, with the rate captured when they were entered, and rolled up so the budget always says what the paperwork says. The estimate is typed once; the actual figure comes from the supplier’s contract and the paid figure from the payments you record against it, and where there is no booking you type the figure and the line says so.

