diff --git a/build.gradle b/build.gradle
index 542e5db4..7efa4725 100644
--- a/build.gradle
+++ b/build.gradle
@@ -208,7 +208,7 @@ task cucumberTestReport(type: TestReport) {
 
 pitest {
     targetClasses = ['org.hostsharing.hsadminng.*']
-    threads = 4
+    threads = 2
 
     // Do not set these limit even lower, they are already pretty bad values!
     // 83%*78% means that only ~66% of the code is properly covered by automated tests.
diff --git a/src/main/java/org/hostsharing/hsadminng/service/dto/CustomerDTO.java b/src/main/java/org/hostsharing/hsadminng/service/dto/CustomerDTO.java
index ff8bf3d8..1e98bfec 100644
--- a/src/main/java/org/hostsharing/hsadminng/service/dto/CustomerDTO.java
+++ b/src/main/java/org/hostsharing/hsadminng/service/dto/CustomerDTO.java
@@ -25,18 +25,25 @@ public class CustomerDTO implements Serializable {
 
     @NotNull
     @Size(max = 400)
+    // visible by >=contractual contact
+    // changeable by >=supporter
     private String contractualAddress;
 
     @Size(max = 80)
+    // visible by >=contractual contact
+    // changeable by >=supporter
     private String contractualSalutation;
 
     @Size(max = 400)
+    // visible by >=contractual contact | >=billing contact
+    // changeable by >=contractual contact
     private String billingAddress;
 
     @Size(max = 80)
+    // visible by >=contractual contact | >=billing contact
+    // changeable by >=contractual contact
     private String billingSalutation;
 
-
     public Long getId() {
         return id;
     }