diff --git a/includes/common.inc b/includes/common.inc
index 20cc82b..319a9af 100644
--- a/includes/common.inc
+++ b/includes/common.inc
@@ -3029,6 +3029,16 @@ function drupal_add_css($data = NULL, $options = NULL) {
     // Always add a tiny value to the weight, to conserve the insertion order.
     $options['weight'] += count($css) / 1000;
 
+    // In case we already have this, re-use the earlier weight.
+    // Else the same files will end up with the same weight
+    // as the count does not change when a file is replaced.
+    // Besides that the latest insertion would count,
+    // but we want the earliest one.
+    if ($options['type'] != 'inline' && isset($css[$data])) {
+      // Re-use the earlier weight.
+      $options['weight'] = $css[$data]['weight'];
+    }
+
     // Add the data to the CSS array depending on the type.
     switch ($options['type']) {
       case 'inline':
@@ -4176,6 +4186,17 @@ function drupal_add_js($data = NULL, $options = NULL) {
   // order of the calls to drupal_add_js().
   $options['weight'] += count($javascript) / 1000;
 
+  // In case we already have this, re-use the earlier weight.
+  // Else the same files will end up with the same weight
+  // as the count does not change when a file is replaced.
+  // Besides that the latest insertion would count,
+  // but we want the earliest one.
+  if ($options['type'] != 'setting'
+    && $options['type'] != 'inline'
+    && isset($javascript[$options['data']])) {
+      $options['weight'] = $javascript[$options['data']]['weight'];
+  }
+
   if (isset($data)) {
     // Add jquery.js and drupal.js, as well as the basePath setting, the
     // first time a JavaScript file is added.