Woocommerce: show the discounted price next to the variation price when the variation is selected - woocommerce

Question

So, I have a woocommerce shop where a 10% discount is applied to all products in the cart and at checkout if a certain payment gateway is used.
My shop has both simple and variable products, and they are all virtual products. I thought of showing on the product page the following information:
the lowest price (for variable products)
the 10% discounted price I could get at checkout.
To do this I used the following code for variable products:
add_filter( 'woocommerce_variable_sale_price_html', 'wpglorify_variation_price_format', 10, 2 );
add_filter( 'woocommerce_variable_price_html', 'wpglorify_variation_price_format', 10, 2 );
function wpglorify_variation_price_format( $price, $product ) {
$prices = array( $product->get_variation_price( 'min', true ), $product->get_variation_price( 'max', true ) );
$price = $prices[0] !== $prices[1] ? sprintf( __( 'A partire da: %1$s (' . $prices[0]*.9 . '€ se paghi online)' , 'woocommerce' ), wc_price( $prices[0] ) ) : wc_price( $prices[0] );
$prices = array( $product->get_variation_regular_price( 'min', true ), $product->get_variation_regular_price( 'max', true ) );
sort( $prices );
$saleprice = $prices[0] !== $prices[1] ? sprintf( __( 'A partire da: %1$s (' . $prices[0]*.9 . '€ se paghi online)' , 'woocommerce' ), wc_price( $prices[0] ) ) : wc_price( $prices[0] );
return $price;
}
For simple products I used this snippet instead:
add_filter( 'woocommerce_get_price_html', 'change_displayed_price_html', 10, 2 );
function change_displayed_price_html( $price, $product ) {
if( $product->is_type('simple') ){
$regular_price = (float) $product->get_regular_price();
$saving_price = $regular_price*.9;
$price .= sprintf( __(' (€%s se paghi online)', 'woocommerce' ), $saving_price );
}
return $price;
}
Everything works fine, but on variable products I have a problem. When I select a variation, I would like to give the same information next to the price being shown and related to that variation. I tried with the following snippet:
add_filter('woocommerce_available_variation', 'variation_custom_text', 10, 3 );
function variation_custom_text( $price, $product, $variation ) {
$variation_price = (float) $product->get_variation_price();
$saving_price = $variation_price*.9;
$price['availability_html'] .= sprintf( __(' (€%s se paghi online)', 'woocommerce' ), $saving_price );
return $price;
}
The problem is that the discounted price is calculated on the price of the first variation, regardless of which variation I select. For example, if variation A = $100, a discounted price of $90 is shown. If I select variation B = $120, a discounted price of $90 is always shown. Where am I doing wrong?
Thanks for your answers.