The need for querying differs between tandems and end offices.

Default Tandem Query Service
Whenever CenturyLink receives an unqueried call at one of its tandems (either local or access), which is terminating to a NPA/NXX that has had at least one number ported, a query is required to efficiently terminate that call.

It does not matter if the dialed number has actually ported, only that the NPA/NXX of the dialed number contains at least one ported number. The carrier that passes CenturyLink the call will be billed the LNP Default Tandem Query Rate for each query successfully completed.

Default End Office Query Service
Whenever CenturyLink receives an unqueried call at one of its end offices that is terminating to a ported number, a query is required to terminate the call.

This is different from Default Tandem Queries, in that only calls to numbers which have actually ported are queried. The carrier that passes CenturyLink the call will be billed the LNP Default End Office Query Rate for each successfully completed query.