Hi TSE1,

change

if($product->sell_price > 0){ $output .= "<".$gg."price>" . $product->sell_price . "\n"; }

to:
if($product->sell_price > 0){ $output .= "<".$gg."price>" . ($product->sell_price*1.19) . "\n"; }

for a 19% tax , 1.20 for 20% tax and so on.