jepser on "[Plugin: WooCommerce - excelling eCommerce] Price not showing when variations have the same price"

Hi!
I'm using variation type product, in this site:
http://elroble.royalworkshop.com/catalogo/calcetin-berlin-sport/

But the prices are not showing, all of them are the same, but when I change one of the prices, it shows the prices for any selection.

Do anyone know why is this happen?

http://wordpress.org/extend/plugins/woocommerce/