I paid the electricity meter ticket, which is a warm reminder. What does it mean to execute 1 step every February?

The implementation of 1 ladder in February every year means that the electricity price is different with different electricity consumption. For example, each household gives 180 kwh of electricity every month. If you use less than 360 degrees of electricity for two months, it is affordable electricity; If you use 400 kwh of electricity for two months, the price of extra 40 kwh of electricity will be higher than that of cheap electricity; If it exceeds more, the price will be higher. These excess electricity bills are settled every two months.