title: Displaying price only when the variation is selected and discount in percentage relatively to the regular price
body: <p>I've this problem. Let me show pictures so I can explain better.</p>
  
  <p>Variation product selected but because all the variations have the same price the price do not show in the bottom:
  <a href="https://i.stack.imgur.com/PDilR.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/PDilR.png" alt="Variation product selected but because all the variations have the same price the price do not show in the bottom."></a></p>
  
  <p>Variation product selected, because they have different PROMO prices they show on top and the regular-promo price after selection:
  <a href="https://i.stack.imgur.com/7XSIl.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7XSIl.png" alt="Variation product selected, because they have different PROMO prices they show on top and the regular-promo price after selection"></a></p>
  
  <p>What I need is that only after selected the variations the price is show in the bottom like the second image and calculation the discount between the promo variation price and the regular variation price. I need the same behavior in the two cases.</p>
  
  <p>I've searched a lot, but none of the things have solved this behavior. Here some answer that are very close: </p>
  
  <ul>
  <li><a href="https://stackoverflow.com/questions/43757920/display-the-discounted-percentage-near-sale-price-in-single-product-pages-for-wc">calculating discount percentage</a> </li>
  <li><a href="https://stackoverflow.com/questions/46005952/woocommerce-variable-products-keep-only-min-price-with-a-custom-label/46009513#46009513">variation prices customizations</a></li>
  </ul>