For the interrupter formula to trigger a price change, a 5-day average NYMEX spot price from the last price change to the current date, will be calculated. If this new average NYMEX spot price changes by ±4 cents per litre over the last NYMEX spot price average, used to set the scheduled price change, the pump price may be adjusted using the new average NYMEX spot price as the baseline. If the interrupter is not triggered on the interruption date, the current pump price will continue until the next price change the following Thursday.