add_action( 'woocommerce_cart_calculate_fees','woocommerce_custom_surcharge' );
function woocommerce_custom_surcharge() {
  global $woocommerce;

	if ( is_admin() && ! defined( 'DOING_AJAX' ) )
		return;

    if(is_user_logged_in() != false){
        $user_meta=get_userdata(get_current_user_id());
        $user_roles=$user_meta->roles;
        if($user_roles[0] == 'administrator'){
            $percentage = 0.20;
            $surcharge = ( $woocommerce->cart->cart_contents_total + $woocommerce->cart->shipping_total ) * $percentage;	
            $woocommerce->cart->add_fee( 'הנחת חבר מועדון', $surcharge, true, '' );
        }else{
            $percentage = 0.10;
            $surcharge = ( $woocommerce->cart->cart_contents_total + $woocommerce->cart->shipping_total ) * $percentage;	
            $woocommerce->cart->add_fee( 'הנחת רכישה חוזרת', $surcharge, true, '' ); 
        }
    }
}