diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/TimeUtil.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/DurationUtil.java
similarity index 82%
rename from org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/TimeUtil.java
rename to org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/DurationUtil.java
index 578c72d87..1123a225e 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/TimeUtil.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/DurationUtil.java
@@ -2,7 +2,7 @@ package org.hl7.fhir.utilities;
 
 import java.util.concurrent.TimeUnit;
 
-public class TimeUtil {
+public class DurationUtil {
   public static String presentDuration(long duration) {
     duration = duration / 1000000;
     String res = "";    // ;
@@ -17,11 +17,11 @@ public class TimeUtil {
         TimeUnit.SECONDS.toMillis(TimeUnit.MILLISECONDS.toSeconds(duration));
 
     if (days > 0)
-      res = String.format("%dd %02d:%02d:%02d.%04d", days, hours, minutes, seconds, millis);
+      res = String.format("%dd %02d:%02d:%02d.%03d", days, hours, minutes, seconds, millis);
     else if (hours > 0)
-      res = String.format("%02d:%02d:%02d.%04d", hours, minutes, seconds, millis);
+      res = String.format("%02d:%02d:%02d.%03d", hours, minutes, seconds, millis);
     else //
-      res = String.format("%02d:%02d.%04d", minutes, seconds, millis);
+      res = String.format("%02d:%02d.%03d", minutes, seconds, millis);
 //    else
 //      res = String.format("%02d.%04d", seconds, millis);
     return res;
diff --git a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/TimeTracker.java b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/TimeTracker.java
index 2a1cf233a..79c236907 100644
--- a/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/TimeTracker.java
+++ b/org.hl7.fhir.utilities/src/main/java/org/hl7/fhir/utilities/TimeTracker.java
@@ -68,29 +68,29 @@ public class TimeTracker {
     CommaSeparatedStringBuilder b = new CommaSeparatedStringBuilder();
     for (Counter c : records) {
       if (c.count == 1) {
-        b.append(c.name+": "+ TimeUtil.presentDuration(c.length));
+        b.append(c.name+": "+ DurationUtil.presentDuration(c.length));
       }
     }
     for (Counter c : records) {
       if (c.count > 1) {
-        b.append(c.name+": "+ TimeUtil.presentDuration(c.length)+" (#"+c.count+")");
+        b.append(c.name+": "+ DurationUtil.presentDuration(c.length)+" (#"+c.count+")");
       }
     }
     return "Times: "+b.toString();
   }
   
   public String clock() {
-    return TimeUtil.presentDuration(System.nanoTime() - globalStart);
+    return DurationUtil.presentDuration(System.nanoTime() - globalStart);
   }
 
   public String instant() {
-    return TimeUtil.presentDuration(System.nanoTime() - globalStart);
+    return DurationUtil.presentDuration(System.nanoTime() - globalStart);
   }
 
   public String milestone() {
     long start = milestone == 0 ? globalStart : milestone ;
     milestone = System.nanoTime();
-    return TimeUtil.presentDuration(milestone - start);
+    return DurationUtil.presentDuration(milestone - start);
   }
 
 }
diff --git a/org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/TimeUtilTest.java b/org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/DurationUtilTest.java
similarity index 53%
rename from org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/TimeUtilTest.java
rename to org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/DurationUtilTest.java
index 75dec18b5..838ae860f 100644
--- a/org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/TimeUtilTest.java
+++ b/org.hl7.fhir.utilities/src/test/java/org/hl7/fhir/utilities/DurationUtilTest.java
@@ -1,12 +1,8 @@
 package org.hl7.fhir.utilities;
 
-import org.hl7.fhir.utilities.xml.XMLUtil;
-import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
-import org.w3c.dom.Document;
-import org.w3c.dom.Element;
 import org.xml.sax.SAXException;
 
 import javax.xml.parsers.ParserConfigurationException;
@@ -19,19 +15,29 @@ import java.util.stream.Stream;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 
-public class TimeUtilTest {
+public class DurationUtilTest {
 
 
   public static Stream<Arguments> data() throws ParserConfigurationException, SAXException, IOException {
     List<Arguments> objects = new ArrayList<>();
     objects.add(Arguments.of("PT0.001S", "00:00.001"));
+    objects.add(Arguments.of("PT0.012S", "00:00.012"));
+    objects.add(Arguments.of("PT0.123S", "00:00.123"));
+    objects.add(Arguments.of("PT0.999S", "00:00.999"));
+    objects.add(Arguments.of("PT1.001S", "00:01.001"));
+    objects.add(Arguments.of("PT1M1.001S", "01:01.001"));
+    objects.add(Arguments.of("PT59M1.001S", "59:01.001"));
+    objects.add(Arguments.of("PT1H1M1.001S", "01:01:01.001"));
+    objects.add(Arguments.of("PT23H1M1.001S", "23:01:01.001"));
+    objects.add(Arguments.of("P1DT23H1M1.001S", "1d 23:01:01.001"));
+    objects.add(Arguments.of("P12DT23H1M1.001S", "12d 23:01:01.001"));
     return objects.stream();
   }
 
   @ParameterizedTest
   @MethodSource("data")
   public void testPresentDuration(String iso8601String, String expectedPresentation) {
-    assertEquals(TimeUtil.presentDuration(Duration.parse(iso8601String).toNanos()), expectedPresentation);
+    assertEquals(expectedPresentation, DurationUtil.presentDuration(Duration.parse(iso8601String).toNanos()));
   }