diff --git a/source/i18n/choicfmt.h b/source/i18n/choicfmt.h
index a72c85ba2af..621ddd8971b 100644
--- a/source/i18n/choicfmt.h
+++ b/source/i18n/choicfmt.h
@@ -409,8 +409,8 @@ inline UnicodeString&
 ChoiceFormat::format(const Formattable& obj,
                      UnicodeString& result,
                      UErrorCode& status) const {
-    // Don't use Format:: - use NumberFormat:: in case base class
-    // modified behavior in future.
+    // Don't use Format:: - use immediate base class only,
+    // in case immediate base modifies behavior later.
     return NumberFormat::format(obj, result, status);
 }
 
diff --git a/source/i18n/smpdtfmt.h b/source/i18n/smpdtfmt.h
index 2e37afb5163..0754d6f037d 100644
--- a/source/i18n/smpdtfmt.h
+++ b/source/i18n/smpdtfmt.h
@@ -725,6 +725,8 @@ inline UnicodeString&
 SimpleDateFormat::format(const Formattable& obj,
                          UnicodeString& result,
                          UErrorCode& status) const {
+    // Don't use Format:: - use immediate base class only,
+    // in case immediate base modifies behavior later.
     return DateFormat::format(obj, result, status);
 }