The commercial time given to advertisers either because an advertisement was preempted or did not receive the exposure that had been agreed to and paid for. (See also, Bonus Spot.)
Spot announcement/commercial run at no charge by a station to replace one that was run at the wrong time, did not run at all or in its entirety, or had technical problems in transmission.
If the tracking process reveals any shortfall of delivery (i.e. ad requests planned versus delivered), adjustments are made by the publisher to the advertiser or agency to ensure proper delivery.
Credit applied to an advertiser's contract when a loss of service occurs or other reasons that might obligate a modification of compensation.