A ProductOffering packaging a UsageVolumeProductSpec may also define ProductOfferingPriceAlterations. These ProductOfferingPriceAlterations overwrite the regular Usage charges (SimpleUsageProdOfferPriceCharge or TariffUsageProdOfferPriceCharge) carried by the ProductOffering that packages the NetworkProductSpec.<br/>If ProductOfferingPriceAlterations are defined out of the package (i.e. when the bucket is empty), it means that the usage is not monitored (i.e. that the user can still use the network product even when the bucket is empty). Else, it corresponds to a blocked package (aka prepaid package) and the user can’t use any more its network product when the bucket is empty.<br/>