Radioreference relies on user submissions to stay up to date. Frequencies must be confirmed as active in order to be valid database submissions.
Digitalfrequencysearch is nothing more than an FCC license aggregator meaning just because frequencies are listed there does not in any way guarantee their active use. Some are active, some aren't. Have a read at the Radioreference data submission guidelines
here to be familiar with what constitites a valid Radioreference database submission
Also Atlantic City Electric has a trunked radio system in the database here:
Delmarva Power / Atlantic City Electric Trunking System Profile
www.radioreference.com