diff --git a/src/blackgui/components/altitudedialog.cpp b/src/blackgui/components/altitudedialog.cpp
index 41b8f5dcf..668ade3be 100644
--- a/src/blackgui/components/altitudedialog.cpp
+++ b/src/blackgui/components/altitudedialog.cpp
@@ -146,7 +146,7 @@ namespace BlackGui
             {
                 if (mode == AltitudeInMetersConvertedToFeet)
                 {
-                    m_altitude = m_altitude.roundedToNearest100ft();
+                    m_altitude = m_altitude.roundedToNearest100ft(true);
                     m_altitudeStr = m_altitude.valueRoundedWithUnit(0);
                 }
 
diff --git a/src/blackmisc/aviation/altitude.cpp b/src/blackmisc/aviation/altitude.cpp
index 1125e419b..48505819c 100644
--- a/src/blackmisc/aviation/altitude.cpp
+++ b/src/blackmisc/aviation/altitude.cpp
@@ -341,7 +341,7 @@ namespace BlackMisc
             // the M/A formats are not supported by VATSIM, means by other clients
 
             // as feed, as none of the other clients
-            const CAltitude a = this->roundedToNearest100ft();
+            const CAltitude a = this->roundedToNearest100ft(false);
             return a.valueRoundedWithUnit(CLengthUnit::ft(), 0);
         }
 
@@ -378,12 +378,12 @@ namespace BlackMisc
             return CLength::compare(*this, otherAltitude);
         }
 
-        CAltitude CAltitude::roundedToNearest100ft() const
+        CAltitude CAltitude::roundedToNearest100ft(bool roundDown) const
         {
             // 23453 => 234.53
             CAltitude a = this->switchedUnit(CLengthUnit::ft());
             const double ft = a.value(CLengthUnit::ft()) / 100.0;
-            const int ftR = qRound(ft) * 100;
+            const int ftR = roundDown ? static_cast<int>(floor(ft)) * 100 : qRound(ft) * 100;
             a.setValueSameUnit(ftR);
             return a;
         }
diff --git a/src/blackmisc/aviation/altitude.h b/src/blackmisc/aviation/altitude.h
index 91354d978..2c3f1c27f 100644
--- a/src/blackmisc/aviation/altitude.h
+++ b/src/blackmisc/aviation/altitude.h
@@ -194,7 +194,7 @@ namespace BlackMisc
 
             //! Round to the nearest 100ft, like needed for China and Russia
             //! \remark https://en.wikipedia.org/wiki/Flight_level
-            CAltitude roundedToNearest100ft() const;
+            CAltitude roundedToNearest100ft(bool roundDown) const;
 
             //! Null altitude (MSL)
             static const CAltitude &null();