diff --git a/java/monasca-common-util/src/main/java/monasca/common/util/stats/SlidingWindowStats.java b/java/monasca-common-util/src/main/java/monasca/common/util/stats/SlidingWindowStats.java
index 96e19753..bff65d32 100644
--- a/java/monasca-common-util/src/main/java/monasca/common/util/stats/SlidingWindowStats.java
+++ b/java/monasca-common-util/src/main/java/monasca/common/util/stats/SlidingWindowStats.java
@@ -98,20 +98,21 @@ public class SlidingWindowStats {
   /**
    * Adds the {@code value} to the statistics for the slot associated with the {@code timestamp} and
    * returns true, else returns false if the {@code timestamp} is outside of the window and
-   * {@code force} is false. If {@code force} is true, always add value
+   * {@code force} is false. If {@code force} is true, always add value to the first window
    * 
    * @param value to add
    * @param timestamp to add value for
-   * @param force if true, add value to first window even if timestamp is outside of all windows
+   * @param force if true, add value to first window
    * @return true if the value was added else false if it the {@code timestamp} was outside the
    *         window and force was false
    */
   public boolean addValue(double value, long timestamp, boolean force) {
-    int index = indexOfTime(timescale.adjust(timestamp));
-    if (index == -1) {
-      if (force) {
-        index = 0;
-      } else {
+    final int index;
+    if (force) {
+      index = 0;
+    } else {
+      index = indexOfTime(timescale.adjust(timestamp));
+      if (index == -1) {
         return false;
       }
     }
diff --git a/java/monasca-common-util/src/test/java/monasca/common/util/stats/SlidingWindowStatsTest.java b/java/monasca-common-util/src/test/java/monasca/common/util/stats/SlidingWindowStatsTest.java
index 6a582da8..8e407268 100644
--- a/java/monasca-common-util/src/test/java/monasca/common/util/stats/SlidingWindowStatsTest.java
+++ b/java/monasca-common-util/src/test/java/monasca/common/util/stats/SlidingWindowStatsTest.java
@@ -170,6 +170,8 @@ public class SlidingWindowStatsTest {
         TimeResolution.ABSOLUTE, 3, 1, 2, 9);
     window.addValue(999, 3, true);
     assertEquals(window.getViewValues(), new double[] { 999 });
+    window.addValue(899, 10, true);
+    assertEquals(window.getViewValues(), new double[] { 899 });
   }
 
   public void shouldNotAddOutOfWindowValueWithoutForce() {
@@ -177,6 +179,8 @@ public class SlidingWindowStatsTest {
         TimeResolution.ABSOLUTE, 3, 1, 2, 9);
     window.addValue(999, 3, false);
     assertEquals(window.getViewValues(), new double[] { Double.NaN });
+    window.addValue(899, 10, false);
+    assertEquals(window.getViewValues(), new double[] { Double.NaN });
   }
 
   public void shouldIgnoreOutOfOrderValue() {