How to view sale prices on single product page and category page?

Hi,
I tested your plugin ??
Everything is OK, but unfortunately I do not see the “sale” price on the category_page and on the single_product_page ??

Here is screenshots:
a) category_page: https://www.dropbox.com/s/joiyybyaoz1w7k1/discount-1.jpg?dl=0
b) single_product_page: https://www.dropbox.com/s/ri50nrug55l0e7m/discount-2.jpg?dl=0

Where am I making a mistake ?

Thank …