diff --git a/src/main/java/com/conveyal/datatools/manager/DataManager.java b/src/main/java/com/conveyal/datatools/manager/DataManager.java
index f437c258d..b1f4c2335 100644
--- a/src/main/java/com/conveyal/datatools/manager/DataManager.java
+++ b/src/main/java/com/conveyal/datatools/manager/DataManager.java
@@ -3,7 +3,7 @@
 import com.conveyal.datatools.common.utils.CorsFilter;
 import com.conveyal.datatools.common.utils.RequestSummary;
 import com.conveyal.datatools.common.utils.Scheduler;
-import com.conveyal.datatools.common.utils.aws.S3Utils;
+import com.conveyal.datatools.common.utils.SparkUtils;
 import com.conveyal.datatools.editor.controllers.EditorLockController;
 import com.conveyal.datatools.editor.controllers.api.EditorControllerImpl;
 import com.conveyal.datatools.editor.controllers.api.SnapshotController;
@@ -55,7 +55,6 @@
 
 import static com.conveyal.datatools.common.utils.SparkUtils.logMessageAndHalt;
 import static com.conveyal.datatools.common.utils.SparkUtils.logRequest;
-import static com.conveyal.datatools.common.utils.SparkUtils.logResponse;
 import static spark.Service.SPARK_DEFAULT_PORT;
 import static spark.Spark.after;
 import static spark.Spark.before;
@@ -130,7 +129,7 @@ static void initializeApplication(String[] args, boolean initScheduledTasks) thr
 
         // Optionally set port for server. Otherwise, Spark defaults to 4567.
         if (hasConfigProperty("application.port")) {
-            PORT = Integer.parseInt(getConfigPropertyAsText("application.port"));
+            PORT = getConfigProperty("application.port").asInt();
             port(PORT);
         }
         useS3 = "true".equals(getConfigPropertyAsText("application.data.use_s3_storage"));
@@ -339,9 +338,7 @@ static void registerRoutes() throws IOException {
         });
 
         // add logger
-        after((request, response) -> {
-            logResponse(request, response);
-        });
+        after(SparkUtils::logResponse);
     }
 
     /**
@@ -363,10 +360,10 @@ private static String resourceToString (String resourceName) {
     }
 
     private static boolean hasConfigProperty(JsonNode config, String name) {
-        String parts[] = name.split("\\.");
+        String[] parts = name.split("\\.");
         JsonNode node = config;
         for (int i = 0; i < parts.length; i++) {
-            if(node == null) return false;
+            if (node == null) return false;
             node = node.get(parts[i]);
         }
         return node != null;
@@ -393,10 +390,10 @@ public static JsonNode getConfigProperty(String name) {
     }
 
     private static JsonNode getConfigProperty(JsonNode config, String name) {
-        String parts[] = name.split("\\.");
+        String[] parts = name.split("\\.");
         JsonNode node = config;
-        for(int i = 0; i < parts.length; i++) {
-            if(node == null) {
+        for (int i = 0; i < parts.length; i++) {
+            if (node == null) {
                 LOG.warn("Config property {} not found", name);
                 return null;
             }
@@ -455,18 +452,25 @@ public static boolean isExtensionEnabled(String extensionName) {
      * In a test environment allows for overriding a specific config value on the server config object.
      */
     public static void overrideConfigProperty(String name, String value) {
-        String parts[] = name.split("\\.");
+        String[] parts = name.split("\\.");
         ObjectNode node = (ObjectNode) serverConfig;
 
-        //Loop through the dot separated field names to obtain final node and override that node's value.
+        // Loop through the dot separated field names to obtain final node and override that node's value.
         for (int i = 0; i < parts.length; i++) {
+            String part = parts[i];
             if (i < parts.length - 1) {
-                if (!node.has(parts[i])) {
-                    node.set(parts[i], JsonUtil.objectMapper.createObjectNode());
+                if (!node.has(part)) {
+                    node.set(part, JsonUtil.objectMapper.createObjectNode());
                 }
-                node = (ObjectNode) node.get(parts[i]);
+                node = (ObjectNode) node.get(part);
             } else {
-                node.put(parts[i], value);
+                // If a value is null, delete the corresponding node instead of put-ting the node value
+                // (After node.put(part, null), calling getConfigPropertyAsText will return "null".)
+                if (value == null) {
+                    node.remove(part);
+                } else {
+                    node.put(part, value);
+                }
             }
         }
     }
diff --git a/src/test/java/com/conveyal/datatools/manager/extensions/mtc/MtcFeedResourceTest.java b/src/test/java/com/conveyal/datatools/manager/extensions/mtc/MtcFeedResourceTest.java
index edac92893..a45ef5c5e 100644
--- a/src/test/java/com/conveyal/datatools/manager/extensions/mtc/MtcFeedResourceTest.java
+++ b/src/test/java/com/conveyal/datatools/manager/extensions/mtc/MtcFeedResourceTest.java
@@ -109,11 +109,7 @@ static void tearDown() {
     @AfterEach
     void resetState() {
         DataManager.overrideConfigProperty(CONFIG_MTC_CREDENTIALS, defaultMtcAwsCredentials);
-
-        String currentMtcRegion = getConfigPropertyAsText(CONFIG_MTC_REGION);
-        if (currentMtcRegion != null && !currentMtcRegion.equals(defaultMtcAwsRegion)) {
-            DataManager.overrideConfigProperty(CONFIG_MTC_REGION, defaultMtcAwsRegion);
-        }
+        DataManager.overrideConfigProperty(CONFIG_MTC_REGION, defaultMtcAwsRegion);
     }
 
     @Test
@@ -262,7 +258,7 @@ void shouldUpdateRtdCarrierProperty(String address) throws JsonProcessingExcepti
     }
 
     @ParameterizedTest
-    @ValueSource(booleans = { false, true })
+    @ValueSource(booleans = { true, false })
     void canUseCorrectMtcCredentials(boolean overwriteDefaults) {
         if (overwriteDefaults) {
             DataManager.overrideConfigProperty(CONFIG_MTC_REGION, "us-west-2");