diff --git a/library/src/calculate_price.cpp b/library/src/calculate_price.cpp
index a5254d0..50ecb09 100644
--- a/library/src/calculate_price.cpp
+++ b/library/src/calculate_price.cpp
@@ -91,7 +91,18 @@ int CALCULATE_LIBRARY_API compute_product_price(Configuration const *cfg, PERMIT
             QVector<ATBTariffProduct> product = products.value();
             if (product.size() > 0) {
                 ATBTariffProduct const &p = product[0];
-                return p.m_tariff_product_price;
+                QTime const &currentTime = QDateTime::currentDateTime().time();
+
+                if (p.m_tariff_product_start <= currentTime && currentTime <= p.m_tariff_product_end) {
+                    return p.m_tariff_product_price;
+                } else {
+                    qCritical() << "(" << __func__ << ":" << __LINE__ << ")"
+                                << "ERROR currentTime"
+                                << currentTime.toString(Qt::ISODate)
+                                << "INVALID ("
+                                << p.m_tariff_product_start.toString(Qt::ISODate)
+                                << p.m_tariff_product_end.toString(Qt::ISODate) << ")";
+                }
             }
         }
     } break;