If I split one invoice across three tax jurisdictions, do I need three separate invoices?

No. One invoice can have three line items, each with a different tax regime applied. The key is that your invoice clearly labels each line by jurisdiction and your GL account structure segregates revenue and tax payable by jurisdiction. Auditors prefer one invoice with three lines over three invoices—it's clearer and harder to lose.

How do I handle rounding when three different tax rates produce fractional amounts?

Calculate all three tax amounts, then adjust the smallest line item's amount or tax to force the total to equal the contract amount. Document the rounding adjustment (usually under ₹1) as a footnote on the invoice. Most auditors accept a single documented rounding variance per invoice.

Indonesia's withholding tax (PPh) is 1.5%—do I show it on the invoice or post it separately?

Show it on the invoice as a separate withholding line. The invoice total (before withholding) should equal your revenue + tax for that line. Withholding reduces the amount you actually receive but does not reduce your invoice total. Your GL shows PPh Receivable (a current asset) when the invoice is created, then clears it when cash arrives with the withholding withheld.

What happens if the delivery split changes mid-contract (e.g., originally 40% Singapore, now 50%)?

Document the change in a contract amendment, dated and signed. On the next invoice, use the new percentages. In your audit file, note the amendment date and the reason for the change. An auditor will ask why the allocation shifted; show them the amendment and you're done. Do not silently change the allocation without documentation.

Multi-country tax invoice proration