[Resolved] wcml_rounded_price() not working

Background of the issue:
I am trying to use the wcml_rounded_price() function to handle rounding of the prices of the products. The function looks like this:

add_filter('wcml_rounded_price', 'wcmlhook_rounded_price', 10, 2);

function wcmlhook_rounded_price($price, $currency)
{
    if ('CZE' == $currency && $price > 10000) {
        $price = ceil($price);
    }
    error_log("Hello World");
    error_log($price);
    error_log($currency);
    return $price + 12.50;
}

Link to a page where the issue can be seen: hidden link

Symptoms:
The price does not change. Function is called but the return value is not displayed as the price of the product.

Questions:
Why is the return value of wcml_rounded_price() not displayed as the price of the product?
Is there a specific reason why the price is not visible despite the function being called?