The government has again revised its tally of passengers aboard the ferry from 475 to 476 and the number of rescued people from 179 to 174 on Friday.
An official at disaster relief headquarters attributed the inconsistency to "overlapping tallies" of the same people as different rescue agencies brought survivors to shore.
The total number of passengers had since the disaster last Wednesday been revised from 477 to 459 to 462 to 475. And the discovery of an unidentified body on Friday night prompted the Ministry of Public Administration and Security to raise the tally to 476.
Staff at ferry operator Chonghaejin Marine said they have no way of knowing whether there were any stowaways on board as some people left the ferry when its departure was delayed due to fog, and some people failed to fill out their personal details when they boarded.
There may also be passengers like truck drivers who boarded the ferry without going through the ticket gate in Incheon.