The Malaysian Government announced in December 1981 that it would adjust Peninsular Malaysia’s time by 30 minutes on 1 January 1982 in order to keep common time with East Malaysia. In view of Singapore’s close relations with Malaysia and also to prevent confusion for travellers and businessmen, the Singapore Government made a very quick decision to follow suit. The change placed Singapore eight hours ahead of GMT. The decision was generally welcomed by most Singaporeans, especially the business community.https://corporate.nas.gov.sg/media/collections-and-research/time-zone-adjustment
Therefore, for Chinese Metaphysics Enthusiast and BaZi Practitioners residing in Singapore, perhaps there is a need to adjust 30min backwards. Because historically during the International Meridian Conference in 1884, when the world was divided into 24 standard time zones, and Singapore was using seven and a half hours ahead of GMT.