Hi L,
There is something I want to ask you. Tony Tan ever answer this question in this forum.
You said you are a logical person, therefore, time convertion is more logical for you.

Have you ever found a different DOB (date) may produce a same chart ? With Si Hua this situation become more obvious, because they just use 18 stars.
You will find a different time of birth, may produce a same chart as well, not just a different day.
Maybe you have a logical explanation for this finding ?
Best regards,
X