Hello XStore Support Team,
I am experiencing a serious issue with the Sales Booster → Quantity Discounts (Multibuy) feature on the cart page.
1. Quantity Discount Recalculation Bug
I have the following tiered discounts set:
Buy 2 → 5% off
Buy 3 → 10% off
Buy 4 → 15% off
Here is the problem:
Increasing quantity works correctly and the correct tier discount is applied.
However, when decreasing quantity across tiers, the discounted price does not revert to the correct tier or original price.
Example:
At quantity 5, the discount is correct.
When reducing quantity back to 1, the cart still shows the discounted price (e.g., the 2-item tier) instead of the original price.
The correct price only appears after manually refreshing the page (F5).
2. This is only happening in the XStore AJAX cart
My progress/free-shipping bar (custom-built) always shows the correct total immediately, which confirms the issue is specifically with the XStore cart update logic, not WooCommerce, not caching, and not my bar.
3. Additional Testing
To verify the issue further, I changed the discount intervals (e.g., from 2–4 → 3–4). The bug behaves the same:
When stepping down across discount tiers, the cart keeps the old tier price.
Only a full page refresh recalculates the correct price.
This confirms that the Sales Booster discount logic is not recalculating during XStore’s AJAX quantity update, which causes:
Incorrect subtotal displayed in the cart
Correct price only shown after refresh or at checkout
Confusing price changes for customers between basket → checkout
4. Impact
Customers see one price in the basket and a different one on checkout after recalculation.
This is a critical issue because it directly affects trust and conversions.
5. Request
Please provide a fix or patch so that Sales Booster Quantity Discounts recalculate correctly during AJAX cart quantity updates, especially when decreasing quantity across tiers (e.g., 5 → 1).
This is a core requirement of any multibuy system and is currently not functioning correctly.
I have provided access to our staging application in the private area.
If you need FTP access, I have also left the details there.
In the video attached, please see me decraese quantity from 5 to 1, it shows the incorrect price £3.39, then I refresh the page and it will show £3.99, my shipping bar I created is the same design as the one provided by yourselves and this always shows the correct amount to get to the £25 free shipping.
Thank you, and please treat this as urgent.
