The actual NTSB report says the passengers were rescued within 80 minutes.
http://www.ntsb.gov/aviationquery/GenPDF.aspx?id=WPR14FA068&rpt=p
On December 11, 2013, at 1522 Hawaiian standard time, a Cessna 208B, N687MA, sustained substantial damage following a loss of engine power and ditching into the Pacific near Kalaupapa, Hawaii.
The language in the report is not clear, whether 80 minutes later was when they started rescuing or finished rescuing, or what the 80 minutes was after. A person would need some concrete times for various events in order to know what they mean. It sounds like the report itself is just reiterating what Kawasaki said had happened.