diff --git a/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java b/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java
index 770826ecfa5..c2ba8b59bf5 100644
--- a/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java
+++ b/server/src/main/java/com/cloud/vm/UserVmManagerImpl.java
@@ -1217,34 +1217,35 @@ public class UserVmManagerImpl extends ManagerBase implements UserVmManager, Vir
     }
 
     /**
-     Updates the instance details map with the current values of the instance for the CPU speed, memory, and CPU number if they have not been specified.
+     Updates the instance details map with the current values for absent details. This only applies to details {@value VmDetailConstants#CPU_SPEED},
+     {@value VmDetailConstants#MEMORY}, and {@value VmDetailConstants#CPU_NUMBER}. This method only updates the map passed as parameter, not the database.
      @param details Map containing the instance details.
-     @param vmInstance The virtual machine instance.
+     @param vmInstance The virtual machine instance to retrieve the current values.
      @param newServiceOfferingId The ID of the new service offering.
      */
 
-    protected void updateInstanceDetails (Map<String, String> details, VirtualMachine vmInstance, Long newServiceOfferingId) {
+    protected void updateInstanceDetailsMapWithCurrentValuesForAbsentDetails(Map<String, String> details, VirtualMachine vmInstance, Long newServiceOfferingId) {
         ServiceOfferingVO currentServiceOffering = serviceOfferingDao.findByIdIncludingRemoved(vmInstance.getId(), vmInstance.getServiceOfferingId());
         ServiceOfferingVO newServiceOffering = serviceOfferingDao.findById(newServiceOfferingId);
-        updateInstanceDetailsKeepCurrentValueIfNull(newServiceOffering.getSpeed(), details, VmDetailConstants.CPU_SPEED, currentServiceOffering.getSpeed());
-        updateInstanceDetailsKeepCurrentValueIfNull(newServiceOffering.getRamSize(), details, VmDetailConstants.MEMORY, currentServiceOffering.getRamSize());
-        updateInstanceDetailsKeepCurrentValueIfNull(newServiceOffering.getCpu(), details, VmDetailConstants.CPU_NUMBER, currentServiceOffering.getCpu());
+        addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(newServiceOffering.getSpeed(), details, VmDetailConstants.CPU_SPEED, currentServiceOffering.getSpeed());
+        addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(newServiceOffering.getRamSize(), details, VmDetailConstants.MEMORY, currentServiceOffering.getRamSize());
+        addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(newServiceOffering.getCpu(), details, VmDetailConstants.CPU_NUMBER, currentServiceOffering.getCpu());
     }
 
     /**
-     * Updates a specific instance detail with the current instance value if the new value is null.
+     * Adds the current detail value to the instance details map if a new value was not specified to it.
      *
-     * @param newValue         the new value to be set
-     * @param details          a map of instance details
-     * @param detailsConstant  the name of the detail constant to be updated
-     * @param currentValue     the current value of the detail constant
+     * @param newValue the new value to be set.
+     * @param details a map of instance details.
+     * @param detailKey the detail to be updated.
+     * @param currentValue the current value of the detail constant.
      */
 
-    protected void updateInstanceDetailsKeepCurrentValueIfNull(Integer newValue, Map<String, String> details, String detailsConstant, Integer currentValue) {
-        if (newValue == null && details.get(detailsConstant) == null) {
+    protected void addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(Integer newValue, Map<String, String> details, String detailKey, Integer currentValue) {
+        if (newValue == null && details.get(detailKey) == null) {
             String currentValueString = String.valueOf(currentValue);
-            logger.debug("{} was not specified, keeping the current value: {}.", detailsConstant, currentValueString);
-            details.put(detailsConstant, currentValueString);
+            logger.debug("{} was not specified, keeping the current value: {}.", detailKey, currentValueString);
+            details.put(detailKey, currentValueString);
         }
     }
 
@@ -1917,7 +1918,7 @@ public class UserVmManagerImpl extends ManagerBase implements UserVmManager, Vir
 
         Map<String, String> cmdDetails = cmd.getDetails();
 
-        updateInstanceDetails(cmdDetails, vm, newServiceOfferingId);
+        updateInstanceDetailsMapWithCurrentValuesForAbsentDetails(cmdDetails, vm, newServiceOfferingId);
 
         boolean result = upgradeVirtualMachine(vmId, newServiceOfferingId, cmdDetails);
         if (result) {
diff --git a/server/src/test/java/com/cloud/vm/UserVmManagerImplTest.java b/server/src/test/java/com/cloud/vm/UserVmManagerImplTest.java
index 4ed0e5b6250..07d2e9bd59f 100644
--- a/server/src/test/java/com/cloud/vm/UserVmManagerImplTest.java
+++ b/server/src/test/java/com/cloud/vm/UserVmManagerImplTest.java
@@ -1454,11 +1454,11 @@ public class UserVmManagerImplTest {
     }
 
     @Test
-    public void updateInstanceDetailsKeepCurrentValueIfNullTestDetailsConstantIsNotNullDoNothing() {
+    public void addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecifiedTestDetailsConstantIsNotNullDoNothing() {
         int currentValue = 123;
 
         for (String detailsConstant : detailsConstants) {
-            userVmManagerImpl.updateInstanceDetailsKeepCurrentValueIfNull(null, customParameters, detailsConstant, currentValue);
+            userVmManagerImpl.addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(null, customParameters, detailsConstant, currentValue);
         }
 
         Assert.assertEquals(customParameters.get(VmDetailConstants.MEMORY), "2048");
@@ -1467,12 +1467,12 @@ public class UserVmManagerImplTest {
     }
 
     @Test
-    public void updateInstanceDetailsKeepCurrentValueIfNullTestNewValueIsNotNullDoNothing() {
+    public void addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecifiedTestNewValueIsNotNullDoNothing() {
         Map<String, String> details = new HashMap<>();
         int currentValue = 123;
 
         for (String detailsConstant : detailsConstants) {
-            userVmManagerImpl.updateInstanceDetailsKeepCurrentValueIfNull(321, details, detailsConstant, currentValue);
+            userVmManagerImpl.addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(321, details, detailsConstant, currentValue);
         }
 
         Assert.assertNull(details.get(VmDetailConstants.MEMORY));
@@ -1481,12 +1481,12 @@ public class UserVmManagerImplTest {
     }
 
     @Test
-    public void updateInstanceDetailsKeepCurrentValueIfNullTestBothValuesAreNullKeepCurrentValue() {
+    public void addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecifiedTestBothValuesAreNullKeepCurrentValue() {
         Map<String, String> details = new HashMap<>();
         int currentValue = 123;
 
         for (String detailsConstant : detailsConstants) {
-            userVmManagerImpl.updateInstanceDetailsKeepCurrentValueIfNull(null, details, detailsConstant, currentValue);
+            userVmManagerImpl.addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(null, details, detailsConstant, currentValue);
         }
 
         Assert.assertEquals(details.get(VmDetailConstants.MEMORY), String.valueOf(currentValue));
@@ -1495,11 +1495,11 @@ public class UserVmManagerImplTest {
     }
 
     @Test
-    public void updateInstanceDetailsKeepCurrentValueIfNullTestNeitherValueIsNullDoNothing() {
+    public void addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecifiedTestNeitherValueIsNullDoNothing() {
         int currentValue = 123;
 
         for (String detailsConstant : detailsConstants) {
-            userVmManagerImpl.updateInstanceDetailsKeepCurrentValueIfNull(321, customParameters, detailsConstant, currentValue);
+            userVmManagerImpl.addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(321, customParameters, detailsConstant, currentValue);
         }
 
         Assert.assertEquals(customParameters.get(VmDetailConstants.MEMORY), "2048");
@@ -1508,16 +1508,16 @@ public class UserVmManagerImplTest {
     }
 
     @Test
-    public void updateInstanceDetailsTestAllConstantsAreUpdated() {
+    public void updateInstanceDetailsMapWithCurrentValuesForAbsentDetailsTestAllConstantsAreUpdated() {
         Mockito.doReturn(serviceOffering).when(_serviceOfferingDao).findById(Mockito.anyLong());
         Mockito.doReturn(1L).when(vmInstanceMock).getId();
         Mockito.doReturn(1L).when(vmInstanceMock).getServiceOfferingId();
         Mockito.doReturn(serviceOffering).when(_serviceOfferingDao).findByIdIncludingRemoved(Mockito.anyLong(), Mockito.anyLong());
-        userVmManagerImpl.updateInstanceDetails(null, vmInstanceMock, 0l);
+        userVmManagerImpl.updateInstanceDetailsMapWithCurrentValuesForAbsentDetails(null, vmInstanceMock, 0l);
 
-        Mockito.verify(userVmManagerImpl).updateInstanceDetailsKeepCurrentValueIfNull(Mockito.any(), Mockito.any(), Mockito.eq(VmDetailConstants.CPU_SPEED), Mockito.any());
-        Mockito.verify(userVmManagerImpl).updateInstanceDetailsKeepCurrentValueIfNull(Mockito.any(), Mockito.any(), Mockito.eq(VmDetailConstants.MEMORY), Mockito.any());
-        Mockito.verify(userVmManagerImpl).updateInstanceDetailsKeepCurrentValueIfNull(Mockito.any(), Mockito.any(), Mockito.eq(VmDetailConstants.CPU_NUMBER), Mockito.any());
+        Mockito.verify(userVmManagerImpl).addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(Mockito.any(), Mockito.any(), Mockito.eq(VmDetailConstants.CPU_SPEED), Mockito.any());
+        Mockito.verify(userVmManagerImpl).addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(Mockito.any(), Mockito.any(), Mockito.eq(VmDetailConstants.MEMORY), Mockito.any());
+        Mockito.verify(userVmManagerImpl).addCurrentDetailValueToInstanceDetailsMapIfNewValueWasNotSpecified(Mockito.any(), Mockito.any(), Mockito.eq(VmDetailConstants.CPU_NUMBER), Mockito.any());
     }
 
     @Test