Billing & Payment

Billing & Payment 

1. Billing Schedule
1.1 Details of billing reception and money transfer can be found in the link provided below.

2. Online Invoicing and Invoice Document Submission

2.1 SUPPLIER can issue invoices at
2.2 Send invoice documents by mail (after the status indicates that the invoice has been received *If the status shows “rejected,” make necessary corrections in the system first).
Important note: Address on the envelope:
To: Finance Department (Attn: Ms. Preaw: Invoice Documents)
Well Graded Engineering Company Limited (Public)
50/1203 Moo 9, Bang Phud, Pak Kret District
Nonthaburi 11120

3. Invoice Document Details
3.1 Invoice/Billing Statement
3.2 Original and Copy of Tax Invoice/Receipt
3.3 Copy of Bank Account Details for First-time Invoicing/Account Number Change
3.4 Copy of Purchase Order (PO) with Approved Signature
3.5 Delivery Note (Must include recipient’s name)
3.6 In cases where both Purchase Order (PO) and Work Order (WO) are involved, invoices must be submitted online through the system.
The company will not accept invoices if the documents are incomplete or not in accordance with the conditions.

4. Payment of Product Charges
4.1 The company will make product payments via bank transfer every 3rd Friday of the month.
4.2 You can inquire about payment amounts one day in advance before the transfer.


Purchase Orders (PO) for materials and Work Orders (WO) for labor should be aligned. Deliverables should be submitted for projects and invoices placed online every Friday.
In case of incomplete or delayed deliverables, payments will be made in the next cycle.

For payment inquiries, contact Ms. Preaw at 02-981-7992-4 ext. 125
For inquiries regarding transferred product payment amounts, contact Ms. Miew at 02-981-7992-4 ext. 110