Two problems with "Virtuemart Sales": tax and graphics

[rooneysoccer]

Good evening.
Yesterday I bought "Virtuemart Sales".
I noted two problems:
1) If I is present "Prices with tax", the discount (%) is increased (?), while the price does not include 22% tax;
2) If I try a word if the result is "zero", the graphics on the page is altered and the bottom of the page goes away by much.
I am attaching two pictures.
Thank you.

[jenkinhill]

You should ask whoever you bought this "Virtuemart Sales" (?plugin) from.