descheduler, I don't quite get it

_sys/descheduler-cronjob.yaml

@@ -5,7 +5,7 @@ metadata:
   name: descheduler-cronjob
   namespace: kube-system
 spec:
-  schedule: "*/20 * * * *"
+  schedule: "*/15 * * * *"
   concurrencyPolicy: "Forbid"
   jobTemplate:
     spec:
@@ -16,7 +16,7 @@ spec:
           priorityClassName: system-cluster-critical
           containers:
           - name: descheduler
-            image: k8s.gcr.io/descheduler/descheduler:v0.20.0
+            image: k8s.gcr.io/descheduler/descheduler:v0.21.0
             volumeMounts:
             - mountPath: /policy-dir
               name: policy-volume

_sys/descheduler-policy-configmap.yaml

@@ -11,17 +11,19 @@ data:
       "RemoveDuplicates":
          enabled: true
       "RemovePodsViolatingInterPodAntiAffinity":
-         enabled: false 
+        enabled: true 
       "LowNodeUtilization":
          enabled: true
          params:
            nodeResourceUtilizationThresholds:
              thresholds:
-               "cpu": 30
-               "memory": 50
+               "cpu": 50
+               "memory": 60
                "pods": 15
              targetThresholds:
-               "cpu": 70
-               "memory": 81
-               "pods": 20 
+               "cpu": 60
+               "memory": 70
+               "pods": 30
+           nodeFit: true
+