1. At the beginning of the year you calculate an average Ø FX rate of your local currency to CHF. This is done on the basis of your closed forward contracts for the current year. This annual Ø hedged rate is used to book your CHF purchases (of goods) on stock.
2. You pay your CHF bills with the FX-rate that was closed for this current month (3 months before) when you get invoiced.
3. The difference between those 2 hedged rates (annual Ø vs. hedged rate of invoiced month) is assigned in cost of sales. = Margin effect of FX-rate. Smoothed by hedging.
4. Each month you check your hedged exposure accordingly to your planned invoices to pay upcoming (3 months ahead) CHF bills. If you have not enough CHF you need to hedge the additional amount. The FX-rate to consider when paying related invoice needs to be adjusted accordingly.
5. At Yearend your foreign currency liquid assets need to be re-valuated by official trading rate valid on 31.12. . Not the foreign currency accounts creditors/debtor accounts. The difference between this yearend rate and the monthly hedged rate in December on you liquid assets is the only impact of currency differences in your financial result.