How to Handle GST Rounding Discrepancies for InvoiceNow Transactions

Overview

When processing GST InvoiceNow transactions in ABSS Accounting/Premier Connect, you may notice a rounding difference between the line-level GST amounts and the invoice-level GST total. This is expected behavior and is not a software bug.

ABSS Accounting/Premier Connect does not allow manual rounding adjustments on GST InvoiceNow transactions to ensure the data submitted to IRAS remains accurate and compliant.

Why This Happens

IRAS allows two acceptable methods to compute the total GST on an invoice when a customer purchases several items: applying 9% to the value of each individual line item, or applying 9% to the sum of all line items. The total GST computed may differ due to rounding depending on which method is used. IRAS

Importantly, IRAS does not require you to file a GST F7 correction for rounding differences where the GST computed by your accounting system is based on each line item while your invoicing system computes GST based on the sum of all line items (or vice versa) — provided you consistently round off the GST computed to the nearest cent (two decimal places) for all tax invoices and credit notes. IRAS

This means: no manual rounding adjustment entry is needed for the InvoiceNow submission itself.

Do I Need to Do Anything?

Scenario	Action Required
Rounding difference between line-level and invoice-level GST	No action needed — IRAS does not impose validation between these amounts
You want your GST reporting to tally exactly with actual GST collected	Create a separate adjustment transaction (see below)

Steps to resolve: Creating a Separate GST Adjustment Transaction

If you want your GST reporting and your sales/purchase records to match the actual GST amount after rounding, you will need to record a separate adjustment entry in ABSS Accounting/Premier Connect. This is separate from the InvoiceNow transaction and does not modify the submitted invoice data.

Steps:

1. Identify the rounding difference amount (e.g. $0.01 or $0.02).
2. Create a General Journal entry or a Credit/Debit Note for the rounding difference.
3. Post it to your GST output tax account.
4. Ensure this adjustment is reflected in your GST F5 return for the relevant period.

💡 This adjustment transaction is for your internal records and GST F5 reconciliation only. It does not need to be submitted as an InvoiceNow document.

IRAS Reference Links

Resource	Link
IRAS – Invoicing Customers (GST rounding methods)	https://www.iras.gov.sg/taxes/goods-services-tax-(gst)/basics-of-gst/invoicing-price-display-and-record-keeping/invoicing-customers
IRAS – Correcting Errors in GST Return (rounding FAQ)	https://www.iras.gov.sg/taxes/goods-services-tax-(gst)/filing-gst/correcting-errors-made-in-gst-return-(filing-gst-f7)
IRAS – GST InvoiceNow Requirement	https://www.iras.gov.sg/taxes/goods-services-tax-(gst)/gst-invoicenow-requirement

Summary

This is working as designed. ABSS Accounting/Premier Connect intentionally prevents rounding adjustments on InvoiceNow transactions to maintain data integrity for IRAS submission. Customers who need their books to reconcile exactly should create a separate manual adjustment entry outside of the InvoiceNow transaction.