Dear K.Oum,
As per conversation by phone with K.Yougyuth and K.Nes, For drop shipment Molex will send original invoice from shipper to you first which original invoice will mention packing list as well.
Molex will checking the clarity of shipping document and provide the detail of packing in email if some shipment not attach the packing list.
For SG tax invoice will send to you later as per internal process of Molex which SG tax invoice will mention original invoice number and AWB number for reference already.
However, cloud you help re-check and enjoin with your shipping for use original invoice with AWB for proceed customs clearance to double check for avoid the same case in the future.
This is the best way with clearly and faster for material control and your BOI.
Please don’t hesitate to contact me if you have any concern.