The fact remains that some of the unknown stories contradict with their earlier writings such as:
Japanese Imperialism Today: "Co-prosperity in Greater East Asia" (Penguin 1973), By Jon Halliday and Gavan McCormack)
Mme Sun Yat-sen (Soong Ching-ling) (Penguin 1986), by Jon Halliday and Jung Chang.
Korea: The Unknown War (Viking 1988), by Jon Halliday and Bruce Cumings.
Have they (Chang & Halliday) attempted to revise, explain, or reconcile with the earlier writings?
People change their views or political perspectives over the years based on the newly discovered "evidence". But any form of evidence such as declassified achieves or interviews must be verified and checked by historians/scholars. This is not only my personal opinion but that of many historians and scholars.