I can't understand the person doing the zoning for international shipping to Malaysia.

Fedex/DHL had group Malaysia as same zone as Indonesia, India , Macau

But another zone for Singapore, Thialand, Taiwan into a different zone

so for shipping to Singapore and Thailand for a pair of QS8 will be cheaper by $200 compared to ship to Malaysia which is sandwich in between Thailand & Singapore.

What's the logic of that?

IIRC international shipping costs are determined by the location of shipping hubs and the which hubs get the long haul flights. Every additional hop costs more $$.

That said, $200 extra sounds really steep.