diff --git a/uc_stock/tests/uc_stock.test b/uc_stock/tests/uc_stock.test
index f563a1a..0cd7e1e 100644
--- a/uc_stock/tests/uc_stock.test
+++ b/uc_stock/tests/uc_stock.test
@@ -92,4 +92,39 @@ class UbercartStockTestCase extends UbercartTestHelper {
     $this->assertTrue(strpos($mail['body'], $this->product->model) !== FALSE, 'Mail body contains SKU.');
     $this->assertTrue(strpos($mail['body'], 'has reached ' . $qty) !== FALSE, 'Mail body contains quantity.');
   }
+
+  public function testStockConsistency() {
+    $this->drupalGet('node/' . $this->product->nid . '/edit/stock');
+    $this->assertText($this->product->title);
+    $this->assertText($this->product->model, 'Product SKU found.');
+
+    $this->assertNoFieldChecked('edit-stock-0-active', 'Stock tracking is not active.');
+    $this->assertFieldByName('stock[0][stock]', '0', 'Default stock level found.');
+    $this->assertFieldByName('stock[0][threshold]', '0', 'Default stock threshold found.');
+
+    $stock = 10;
+    $edit = array(
+      'stock[0][active]' => 1,
+      'stock[0][stock]' => $stock,
+      'stock[0][threshold]' => 3,
+    );
+    $this->drupalPost(NULL, $edit, t('Save changes'));
+
+    // now change sku
+    $this->drupalGet('node/' . $this->product->nid.'/edit');
+    $edit = array('model'=>$this->product->model .'t');
+    $this->drupalPost(NULL, $edit, t('Save'));
+
+    // check stock for old and new sku
+    $this->assertNotEqual($stock, uc_stock_level($this->product->model));
+    $this->assertEqual($stock, uc_stock_level($this->product->model.'t'));
+    // also check in form
+    $this->drupalGet('node/' . $this->product->nid . '/edit/stock');
+    $this->assertFieldChecked('edit-stock-0-active', 'Stock tracking is active.');
+    $this->assertFieldByName('stock[0][stock]', $stock, 'Stock level maintained');
+    $this->assertFieldByName('stock[0][threshold]', 3, 'Setted stock threshold found.');
+  }
+
+  // missing:test this t('SKU @newmodel in use, not updated',array('@newmodel'=>$newmodel))
+
 }
diff --git a/uc_stock/uc_stock.module b/uc_stock/uc_stock.module
index df4ce7c..b76d4b6 100644
--- a/uc_stock/uc_stock.module
+++ b/uc_stock/uc_stock.module
@@ -295,3 +295,84 @@ function uc_stock_increment_product_stock($product, $key, $order) {
   $product->qty = -$product->qty;
   return uc_stock_adjust_product_stock($product, $key, $order);
 }
+
+/**
+ * Implements hook_node_delete().
+ * Clean stock info not needed anymore
+ * and remove conflict for new added product with same sku
+ */
+function uc_stock_node_delete($node) {
+  db_delete('uc_product_stock')
+    ->condition('nid',$node->nid)
+    ->execute();
+}
+
+/**
+ * Implements hook_node_presave().
+ * http://api.drupal.org/api/drupal/modules%21node%21node.api.php/function/hook_node_update/7#comment-21434
+ * and in code of node.module node_save() use original
+ */
+function uc_stock_node_presave($node) {
+  if(uc_product_is_product($node)) {
+    $r  = db_select('uc_product_stock','stock')
+      ->fields('stock')
+      ->condition('sku',$node->model)
+      ->execute()
+      ->fetchAssoc();
+    if($r) { // wayback: do not update
+      $newmodel = $node->model;
+      $node->model = $node->original->model;
+      drupal_set_message(t('SKU @newmodel in use, not updated',array('@newmodel'=>$newmodel)));
+    }
+  }
+}
+
+/**
+ * Implements hook_node_update().
+ */
+function uc_stock_node_update($node) {
+  if($node->original->model != $node->model) {
+    drupal_set_message('stock table updated');
+    db_update('uc_product_stock')
+      ->fields(array('sku' => $node->model))
+      ->condition('sku', $node->original->model)
+      ->execute();
+  }
+}
+
+/**
+ * implements hook_form_FORM_ID_alter() for uc_product_adjustments_form().
+ *
+ * Save a copy of the original form values and insert our own submission
+ * function for product adjustments so we can update stock when model is changed
+ * for an attribute.
+ */
+function uc_stock_form_uc_product_adjustments_form_alter(&$form, &$form_state, $form_id) {
+  $form['original_body'] = array(
+    '#type' => 'value',
+    '#value' => $form['table']['body'],
+  );
+  $form['#submit'][] = 'uc_stock_form_uc_product_adjustments_form_submit';
+}
+
+/**
+ * Submission function for uc_product_adjustments_form().
+ *
+ * Update the stock table if the model number has changed for the variant.
+ *
+ * @see uc_product_adjustments_form_submit()
+ */
+function uc_stock_form_uc_product_adjustments_form_submit($form, &$form_state) {
+  foreach ($form_state['values']['body'] as $key => $value) {
+    $default_model = $form_state['values']['default'];
+    $old_model = !empty($form_state['values']['original_body'][$key]['model']) ? $form_state['values']['original_body'][$key]['model']['#default_value'] : '';
+    $new_model = !empty($value['model']) ? $value['model'] : '';
+    if ($old_model != $new_model) {
+      db_update('uc_product_stock')
+        ->fields(array('sku' => $new_model))
+        ->condition('sku', $old_model)
+        ->execute();
+      drupal_set_message(t('Updated stock table: changed sku @old_model to @new_model', array('@old_model' => $old_model, '@new_model' => $new_model)));
+    }
+  }
+}