diff --git a/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingHighestDenseStore.java b/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingHighestDenseStore.java
index f52d695..4ccdfa6 100644
--- a/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingHighestDenseStore.java
+++ b/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingHighestDenseStore.java
@@ -96,7 +96,7 @@ public void mergeWith(Store store) {
     if (store instanceof CollapsingHighestDenseStore) {
       mergeWith((CollapsingHighestDenseStore) store);
     } else {
-      getAscendingStream().forEachOrdered(this::add);
+      store.getAscendingStream().forEachOrdered(this::add);
     }
   }
 
diff --git a/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingLowestDenseStore.java b/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingLowestDenseStore.java
index 0f96e02..d46e73a 100644
--- a/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingLowestDenseStore.java
+++ b/src/main/java/com/datadoghq/sketch/ddsketch/store/CollapsingLowestDenseStore.java
@@ -96,7 +96,7 @@ public void mergeWith(Store store) {
     if (store instanceof CollapsingLowestDenseStore) {
       mergeWith((CollapsingLowestDenseStore) store);
     } else {
-      getDescendingStream().forEachOrdered(this::add);
+      store.getDescendingStream().forEachOrdered(this::add);
     }
   }