Titanic or Olympic- Which Ship Sank?

[Cheryl Turner]

I am currently reading Titanic or Olympic- Which Ship Sank by Steve Hall and Beveridge. However, on pg 94 it states, "Olympic disguised as Titanic would then have been required to depart Belfast not long after dawn.....to make it back to Southampton in time for departure on 3 April". Surely this should be the other way round; Titanic disguised as Olympic if the switch theory is to hold?