code: protected function isDiscountUpdateNeeded(SaleInterface $sale)
      {
          if ($this->persistenceHelper->isChanged($sale, ['autoDiscount'])) {
              return true;
          }
  
          if ((0 == $sale->getPaidTotal()) && $this->persistenceHelper->isChanged($sale, ['customerGroup', 'customer'])) {
              return true;
          }
  
          return $this->didInvoiceCountryChanged($sale);
      }
docs: Returns whether or not the discount adjustments should be updated.
  
  @param SaleInterface $sale
  
  @return bool