diff --git a/Energy_Pie/module.php b/Energy_Pie/module.php
index 75d6e1e..d5ff57c 100644
--- a/Energy_Pie/module.php
+++ b/Energy_Pie/module.php
@@ -176,7 +176,11 @@ class Energy_Pie extends IPSModule
         if (empty($values)) {
             return 0.0;
         }
-        usort($values, static fn($a, $b) => (int)$a['TimeStamp'] <=> (int)$b['TimeStamp']);
+        $firstTs = (int)$values[0]['TimeStamp'];
+        $lastTs  = (int)$values[count($values) - 1]['TimeStamp'];
+        if ($firstTs > $lastTs) {
+            $values = array_reverse($values);
+        }
         $dbg['count'] = count($values);
         $dbg['first'] = (float)$values[0]['Value'];
         $dbg['last']  = (float)$values[count($values) - 1]['Value'];