curcy and woo discount rules plugin compatibility

Hello,
I am using plugin woo discount rules pro (from flycart) for discounted prices.
When I activate curcy and in my other plugin I call folloving method via ajax, the discount rules plugin is not working. When I deactivate curcy, the prices are discounted in folloving method.

`function calculate_cart_subtotal() {
$include_tax = wc_tax_enabled();
$subtotal = 0;

foreach ( WC()->cart->get_cart() as $cart_item_key => $cart_item ) {
$line_total = $cart_item[‘line_total’];
$line_tax = $cart_item[‘line_tax’];
$_product = apply_filters( ‘woocommerce_cart_item_product’, $cart_item[‘data’], $cart_item, $cart_item_key );

if (isset($cart_item[‘provize’]) && $cart_item[‘provize’] * 1 === 1) {
// speciální podmínka pro provizi
} else if (stripos($_product->get_sku(), ‘GVTB’) !== false) {
// speciální podmínka pro produkty s určitým SKU
} else {
$subtotal += round($line_total, 2) + round($line_tax, 2);
}
}

return round($subtotal,2);
}