show estimate date as a count of working days from today that is simple sum of (preparation days + shipping days)

gistfile1.txt

add_filter('pisol_edd_product_estimate', function($estimate){
	$min = (int) ($estimate['min_preparation_days'] ?? 0) + (int) ($estimate['min_shipping_days'] ?? 0);
	$max = (int) ($estimate['max_preparation_days'] ?? 0) + (int) ($estimate['max_shipping_days'] ?? 0);
	$estimate['min_days'] = $min;
	$estimate['max_days'] = $max;
	return $estimate;
});

add_filter('pisol_edd_get_order_estimate', function($estimate){
	$min = (int) ($estimate['min_preparation_days'] ?? 0) + (int) ($estimate['min_shipping_days'] ?? 0);
	$max = (int) ($estimate['max_preparation_days'] ?? 0) + (int) ($estimate['max_shipping_days'] ?? 0);
	$estimate['min_days'] = $min;
	$estimate['max_days'] = $max;
	return $estimate;
});