There are many elements that can go into the overall price of your shipment. These depend on seasonality, commodity, destination, and other factors beyond your control. Surcharges such as the General Rate Increase (GRI) and Emergency Bunker Surcharge (EBS) can be announced at the last minute and be applicable to your shipment. In the US, under FMC guidelines, carriers must allow for a 30-day cushion for GRIs to come into effect.