Why put colonial customs officers under central government?
Short answerTheir authority and appointments would depend on central government, giving the government an influential official inside the local commercial community.
NotesThe intended independence was from the colonial governor. Officers appointed by customs authorities in England would owe their position and much of their power to central government. Their ability to arrest people and control activity involving ports and merchants gave them considerable local influence. In this interpretation, those appointments were a means of integrating colonial communities more closely into English government.