Attorney Leonard M. Singer, Boston, MA  (617) 737-7670  (

Excerpt from:

49 CFR 377.209. Additional charges.

When a carrier--

(a) Has collected the amount of tariff charges represented in a freight bill presented by it as the total amount of such charges, and

(b) Thereafter presents to the shipper another freight bill for additional charges-- the carrier may extend credit in the amount of such additional charges for a period of 30 calendar days from the date of the presentation of the freight bill for the additional charges.