为什么我的WooCommerce自定义费用在我调用get_fee时消失但仍包括在内？

I added a WooCommerce custom fee depending on the cart value, and I try to get this fee on a custom quote page, but when I call the WC()->cart->get_fees() function, it's always empty even if the total price include my custom fee.

This is how I added my custom fee :

add_action('woocommerce_cart_calculate_fees' , 'custom_discount');
function custom_discount( ){
    if( WC()->cart->subtotal >= 150 ):
        $discount = WC()->cart->subtotal * -0.03;
        WC()->cart->add_fee( 'Remise au volume : 3%', $discount);
    endif;
}

Everything is fine on my cart and checkout page, but I created a page-quote.php to print a quote, and even if the wc_cart_totals_order_total_html() is giving me the price with my discount, the WC()->cart->get_fees() function is always giving me an empty array...

Related issue not really helpful : Custom WooCommerce fee disappears at checkout

UPDATE

When I do a simple print_r( WC()->cart ) to see what's inside, I can see my fees in the [total] array. I don't know what's happening with those fees...

[totals:protected] => Array
        (
            [subtotal] => 6000.00
            [subtotal_tax] => 0
            [shipping_total] => 30.00
            [shipping_tax] => 0
            [shipping_taxes] => Array
                (
                )

            [discount_total] => 0
            [discount_tax] => 0
            [cart_contents_total] => 6000.00
            [cart_contents_tax] => 0
            [cart_contents_taxes] => Array
                (
                )

            [fee_total] => -900.00
            [fee_tax] => 0
            [fee_taxes] => Array
                (
                )

            [total] => 5130.00
            [total_tax] => 0
        )

UPDATE 2

When I add the hook do_action('woocommerce_cart_calculate_fees') right after the do_action('get_header') of my page template, I can see fees in my WC()->cart->get_fees().

I don't think it's the best way to do this thing, but at least it works for now...