A provision approved by the regulatory agency allowing a company to make filings to change its rates, without the usual suspension period, for the purpose of recovering currently the changes in its cost of purchased gas. Pipelines with such tariff provisions are permitted to charge all purchased gas costs, net of storage injections and withdrawals, to a deferred expense account. As gas is sold, the deferred account is credited by an amount equal to the volume of gas sold multiplied by the base average cost and Btu content of gas used in the last rate filing. The difference between the charges and credits to this account is accumulated with interest and billed out to customers over the next annual period as a purchased gas surcharge (positive or negative) adjustment.