Hey Cheewarat,
I am happy to share with you the investigation outcome: both claims are confirmed by International Mail and SingPost CS.
SingPost claim team will liaise with you to prepare the claim form (the amt. is capped at S$68 so pending on the declared value, whichever is lower)
Hope this will help my TH CS team a bit. (confirmation email is attached here for reference)
Thanks a lot,