It is not possible.
We need to submit a full set of customs declaration doc for customs clearance purpose based on our sales value, which is booked in CUSTOMS SYSTEM and FOREIGN EXCHANGE BUAREA, meanwhile, we need to attached commercial invoice, this invoice should be exactly the same as our declared value (sales value) in customs system.
If we take your invoice USD400.00 with the goods, while our customs paper showed export value as CNY1166.00(USD185.52), this delivery will be rejected either by DHL or CUSTOMS.
I made a call to DHL just now, they confirm the commercial invoice amount should be exactly the same as our sales value on customs declaration paper.
In such case, I am afraid we can only have the parts deliver to Thailand consigned to BJC.