WC Fields Factory

The plugin URL: https://wordpress.org/plugins/wc-fields-factory/

In file functions.php add next code:

add_filter('wcff_negotiate_price_after_calculation', function($price) {
    if (class_exists('WOOCS')) {
        global $WOOCS;
        if ($WOOCS->is_multiple_allowed) {
            $currencies = $WOOCS->get_currencies();
            $conversion_rate = $currencies[$WOOCS->current_currency]['rate'];
            $price = $price / $conversion_rate;
        }
    }

    return $price;
});