Especially for those living in Malaysia and Singapore, it is important to know that throughout the years, the government has adjusted the timing numerous times due to political purposes.
Please read this article for a clear and thorough understanding on why the time of birth needed to be adjusted.
Many Masters out there do not have the knowledge or simply do not want to make the efforts to adjust a person's birth time to get the accurate birth chart. If our BaZi is derived from our birth year, month, date and time, how can a wrong time provides one an accurate chart?