Dear Rungnapa S,
For the item 6, it shall be showed “N/M” which means is “NO Marking”, so there is no difference.
After discussion with you via telephone, please note CO or form _E is for reduce your import TAX only, not effect your clean custom.
By the way, we also noted there is no special requirement to do Form-E in your PO, so we just do the standard CO to evidence the cargo original from China.