A custom snippet in my WooCommerce functions file is causing every fixed-amount coupon to rise by exactly 10 % (our VAT rate) the moment it’s applied at checkout. A €50 voucher shows up as a €55 discount, throwing off all order totals and reports. I need someone who can: • inspect the current child-theme / mini-plugin code, locate the hook or filter that alters WC_Cart coupon calculations, and remove or rewrite it so a fixed coupon always deducts its face value only • test the fix on my staging clone under two tax zones (standard 10 % and zero-rated) to confirm that product tax is still calculated correctly while the coupon itself remains tax-neutral • supply a concise change log or Git diff so I can keep the store update-safe You’ll be working with the latest WooCommerce, PHP 8.1, and a handful of common extensions. No design work is needed—just a clean, well-commented PHP adjustment that resolves the mis-calculation without side effects.