Vietnam timezone history probably wrong - another example

[Alois Treindl]

I have found another source indicating that Vietnam was on  UTC+8h in 
early April 1969, and not on UTC+7h as current tzdata claims.

The source is a personal war memoir,
http://www.military.com/Content/MoreContent?file=fowler01

The author writes in the second paragraph (refering to his trip to 
Vietnam around April 10, 1969):
----- quote
There is a 14 hour time difference between South Vietnam and Central 
Standard Time here in the United States.
----- end quote
Again, this is consistent with Vietnam being on 8h east at that time. 
Central Standard Time is 6h west, making the difference 14 hours.