diff --git a/JavaSource/org/unitime/timetable/action/SchedulingSubpartEditAction.java b/JavaSource/org/unitime/timetable/action/SchedulingSubpartEditAction.java
index 6a4d05d685..91ec5e7ca0 100644
--- a/JavaSource/org/unitime/timetable/action/SchedulingSubpartEditAction.java
+++ b/JavaSource/org/unitime/timetable/action/SchedulingSubpartEditAction.java
@@ -340,10 +340,10 @@ private void doLoad(SchedulingSubpart ss, String subpartId ) {
 	        	form.setCreditType(credit.getCreditType().getUniqueId());
 	        	form.setCreditUnitType(credit.getCreditUnitType().getUniqueId());
 	        	if (credit instanceof FixedCreditUnitConfig){
-	        		form.setUnits(((FixedCreditUnitConfig) credit).getFixedUnits());
+	        		form.setUnits(toString(((FixedCreditUnitConfig) credit).getFixedUnits()));
 	        	} else if (credit instanceof VariableFixedCreditUnitConfig){
-	        		form.setUnits(((VariableFixedCreditUnitConfig) credit).getMinUnits());
-	        		form.setMaxUnits(((VariableFixedCreditUnitConfig) credit).getMaxUnits());
+	        		form.setUnits(toString(((VariableFixedCreditUnitConfig) credit).getMinUnits()));
+	        		form.setMaxUnits(toString(((VariableFixedCreditUnitConfig) credit).getMaxUnits()));
 	        		if (credit instanceof VariableRangeCreditUnitConfig){
 	        			form.setFractionalIncrementsAllowed(((VariableRangeCreditUnitConfig) credit).isFractionalIncrementsAllowed());
 	        		}
@@ -444,18 +444,27 @@ private void doUpdate(SchedulingSubpart ss, SchedulingSubpartDAO sdao, boolean t
         				CourseCreditUnitConfig origConfig = ss.getCredit();
             			ss.setCredit(null);
             			sdao.getSession().remove(origConfig);
-            			ss.setCredit(CourseCreditUnitConfig.createCreditUnitConfigOfFormat(form.getCreditFormat(), form.getCreditType(), form.getCreditUnitType(), form.getUnits(), form.getMaxUnits(), form.getFractionalIncrementsAllowed(), Boolean.valueOf(false)));
+            			ss.setCredit(CourseCreditUnitConfig.createCreditUnitConfigOfFormat(
+            					form.getCreditFormat(), form.getCreditType(), form.getCreditUnitType(),
+            					toFloat(form.getUnits()), toFloat(form.getMaxUnits()),
+            					form.getFractionalIncrementsAllowed(), Boolean.valueOf(false)));
             			ss.getCredit().setOwner(ss);
         			}
         		} else {
         			CourseCreditUnitConfig origConfig = ss.getCredit();
         			ss.setCredit(null);
         			sdao.getSession().remove(origConfig);
-        			ss.setCredit(CourseCreditUnitConfig.createCreditUnitConfigOfFormat(form.getCreditFormat(), form.getCreditType(), form.getCreditUnitType(), form.getUnits(), form.getMaxUnits(), form.getFractionalIncrementsAllowed(), Boolean.valueOf(false)));
+        			ss.setCredit(CourseCreditUnitConfig.createCreditUnitConfigOfFormat(
+        					form.getCreditFormat(), form.getCreditType(), form.getCreditUnitType(),
+        					toFloat(form.getUnits()), toFloat(form.getMaxUnits()),
+        					form.getFractionalIncrementsAllowed(), Boolean.valueOf(false)));
         			ss.getCredit().setOwner(ss);
         		}
         	} else {
-    			ss.setCredit(CourseCreditUnitConfig.createCreditUnitConfigOfFormat(form.getCreditFormat(), form.getCreditType(), form.getCreditUnitType(), form.getUnits(), form.getMaxUnits(), form.getFractionalIncrementsAllowed(), Boolean.valueOf(false)));
+    			ss.setCredit(CourseCreditUnitConfig.createCreditUnitConfigOfFormat(
+    					form.getCreditFormat(), form.getCreditType(), form.getCreditUnitType(),
+    					toFloat(form.getUnits()), toFloat(form.getMaxUnits()),
+    					form.getFractionalIncrementsAllowed(), Boolean.valueOf(false)));
     			ss.getCredit().setOwner(ss);
         	}
         }
@@ -485,6 +494,19 @@ private void doUpdate(SchedulingSubpart ss, SchedulingSubpartDAO sdao, boolean t
         sdao.getSession().flush();
     }
     
+    protected static Float toFloat(String value) {
+    	try {
+    		return Float.valueOf(value);
+    	} catch (Exception e) {
+    		return 0f;
+    	}
+    }
+    
+    protected static String toString(Float value) {
+    	if (value == null) return "";
+    	return value.toString();
+    }
+    
     protected void setupChildren(SchedulingSubpart ss) {
 		DatePattern selectedDatePattern = (form.getDatePattern() < 0 ? (ss.canInheritParentPreferences() ? ss.getParentSubpart().effectiveDatePattern() : ss.getSession().getDefaultDatePatternNotNull()) : DatePatternDAO.getInstance().get(form.getDatePattern()));
 		try {
diff --git a/WebContent/help/Release-Notes.xml b/WebContent/help/Release-Notes.xml
index 35f5903a5c..b5f5ec7561 100644
--- a/WebContent/help/Release-Notes.xml
+++ b/WebContent/help/Release-Notes.xml
@@ -44,6 +44,13 @@
 				</line>
 			</description>
 		</item>
+		<item>
+			<name>Edit Scheduling Subpart: Subpart Credit</name>
+			<description>
+				<line>Max Units made editable when editing Variable Min/Max credit without the need to change the credit type first (when editing existing credit information).</line>
+				<line>Fixed an issue when no units or max units are provided (for a type that requires units/max units) or when the provided units are not a number.</line>
+			</description>
+		</item>
 		<item>
 			<name>Course Timetabling Solver: Optimization</name>
 			<description>
diff --git a/WebContent/user/schedulingSubpartEdit.jsp b/WebContent/user/schedulingSubpartEdit.jsp
index 5cf3def90a..b724783a6f 100644
--- a/WebContent/user/schedulingSubpartEdit.jsp
+++ b/WebContent/user/schedulingSubpartEdit.jsp
@@ -209,7 +209,7 @@
 				<td nowrap><loc:message name="propertyMaxUnits"/></td>
 				<td>
 				<s:textfield name="form.maxUnits" maxlength="4" size="4"
-					disabled="%{form.creditFormat != 'variableRange'}"/>
+					disabled="%{form.creditFormat != 'variableRange' && form.creditFormat != 'variableMinMax'}"/>
 				</td>
 				</tr>
 				<tr>