Quantity Pricing plugin issue with mini cart

[goclimbing]

We're using the WooCommerce Precious Metal Discounts and Payment Fees plugin by IgniteWoo. It's the obvious choice for us since we also use their PlatformGold for WooCommerce plugin which does our product import and price updates via API.

I recorded a Loom for the developer (Mark) over at IgniteWoo but we're to the point it's time to post here.

As you'll see the line item total and product price change are not being corrected properly:
www.loom.com/share/c57b0e9868944b87a57f79e39f298402

we did some digging into ajax-cart.php but we're now stumped.
Adding this line had some effect (updated quantity which wasn't working) but didn't fix the problem.

line 558
//WC()->cart->calculate_totals(); //added for Metals discount plugin attempted fix
$items = WC()->cart->get_cart()