Feature
GST-exempt artworks and GST-applicable products live in the same cart at most centres. Freight has its own tax line. SAM's accounting expects each split correctly or the books don't reconcile. Defyn SAM does this automatically on every order push — so customer totals match SAM to the cent and your bookkeeper stops sending order spreadsheets back with red highlights.
Works on Shopify and WordPress / WooCommerce.
Generic SAM-to-WooCommerce or SAM-to-Shopify connectors treat tax as a single number. AU sales tax requires per-line handling, and the mistakes are silent — orders push to SAM looking fine, and the mismatch only surfaces at end-of-month reconciliation.
Defyn SAM stores a per-product GST flag (sam_gst_amount) when it syncs the product down. On order push, it uses that flag — not a blanket assumption — to decide how each line is split.
For each line item, the plugin reads the sam_gst_amount post meta that was stored at sync time. If it's zero, the line is GST-exempt. If it's positive, GST applies.
If WC reports zero subtotal_tax on a GST-applicable line, we back-calculate ExGST from the gross using the configured gst_rate (default 0.10). If the line is GST-exempt, we send ExGST = gross. If WC already has the tax split, we honour it.
Shipping isn't a product line. It goes into an "Other" entry with the SAM freight CategoryId you configured in Settings, with SaleAmount = shipping_total + shipping_tax and ExGST = shipping_total. SAM's freight ledger reconciles automatically.
Before sending, the plugin verifies the sum of every line's SaleAmount matches the WC order total to the cent. Mismatches are logged with line-by-line detail before the push, so they're caught at the source instead of weeks later in reconciliation.
Scenario: A $400 artwork sold via WooCommerce. SAM ships this category GST-exempt.
Result: Pre-Defyn: ExGST=$363.64, GST=$36.36 in SAM — wrong. Defyn SAM: ExGST=$400, SaleAmount=$400, no GST recorded. SAM's invoice for the customer matches the website to the cent.
Scenario: A cart with a $400 GST-exempt artwork + a $100 GST-applicable ceramic + $50 shipping.
Result: Three distinct splits — artwork at ExGST=400/GST=0, ceramic at ExGST=90.91/GST=9.09, freight at ExGST=45.45/GST=4.55 — all sent in one push. The customer paid $550 gross; SAM records $550 gross. No reconciliation discrepancy.
Scenario: An admin changes the SAM gst_rate from 10% to 0% during a tax holiday.
Result: The plugin's reconciliation rate is configurable in Settings. Change it to 0.0 and the back-calculation skips. No code change required.
Then WC reports the tax correctly per line, and the plugin honours those values instead of back-calculating. The reconciliation only kicks in for lines where WC reports zero tax — typically because the centre didn't configure WC tax classes (which is the common case).
On product sync from SAM, the plugin stores a sam_gst_amount post meta value for each product. SAM's API tells us this per product. If GST=0 on the SAM record, that meta is set to 0 and the line is treated as exempt on every subsequent order push.
Yes. The plugin logs the full SAM payload for every order push with line-level detail (SaleAmount, ExGST, CategoryId per item). Visible in Tools → Sync logs in the admin. Supports diagnostics in a single click.
Australian art centres typically use WC tax exemption rules per shipping zone for international orders. Those zero out the tax, and the plugin's reconciliation treats them as already-correct (it only back-calculates for AU buyers where GST should have been collected).
Yes — it's where most generic connectors leak money. SAM expects freight as a separate accounting line; off-the-shelf plugins fold it into the product totals and SAM either misses it or double-counts it. The Hermannsburg mismatch we found in late 2025 was exactly this — $17 per order silently disappearing from freight reconciliation. Defyn SAM fixes it at the source.
Want a 15-minute screenshare against your actual SAM data? Send us a quick note or call — we’ll line up a walkthrough at a time that suits.
