Incorrect billTotal

On Joomla ‎5.4.1 with VirtueMart 4.6.4 11226, VP One Page Checkout 7.35 and AwoCoupon 4.1.0.1

When applying a coupon the total calculation is incorrect, for example I have a salesPrice of $425 and salesPricePayment of 6.472081218274127, the billTotal comes to 431.4720812182741

After applying a coupon of 30% created via AwoCoupon, the salesPriceCoupon would be at -127.5 and salesPricePayment at 4.530456852791872 which are correct but the billTotal is 300.0888324873097 when it should be 302.0304568527919

Applying a 30% coupon created via virtuemart would have the correct billTotal.

I have tried changing the Tax calculation (Coupons) to both Discount after tax and Discount before tax but neither changes this figure.

Would you know what other settings that could be affecting this?

Best regards

Thanks for getting back, the salesPricePayment is the transaction fee via Stripe of 1.5%, as for tax rules, there's a Marge of 15 added to each individual item.

The billTotal is correct for an older version (Awocoupon 3.6.0.12, VirtueMart 4.0.12 10777)

For the current version to circumvent the issue commenting out the line

$this->vmcartPrices['billTotal'] -= ( $orig_sales_price - $this->vmcartPrices['salesPricePayment'] );

on line 546 in the file  \administrator\components\com_awocoupon\helper\estore\virtuemart\class-awocoupon-helper-estore-virtuemart-discount.php would solve the issue