Your gas meter is generally read on a regularly scheduled basis by AGLC. Typically, the time between meter readings (called service periods) is 27-33 days. As long as your service period is within that normal range, we will charge you your Guaranteed Bill amount regardless of how much gas you use that month. However, sometimes other factors, such as when you start new service with us, can cause your service period to be less than 27 days (or greater than 33 days). We do not think it would be right to charge you a full Guaranteed Bill amount for an unusually short time period. For example, if you start with GNG on the 1st of the month, and your meter is read on the 3rd, this service period would be only 3 days. In those instances, your bill will be prorated to reflect the actual duration of your service period. If your billing period spans longer than 33 days, it will also be prorated.