diff --git a/sale_start_end_dates/__manifest__.py b/sale_start_end_dates/__manifest__.py
index 6f003efb7d7..a963cf8e91c 100644
--- a/sale_start_end_dates/__manifest__.py
+++ b/sale_start_end_dates/__manifest__.py
@@ -5,7 +5,7 @@
 
 {
     "name": "Sale Start End Dates",
-    "version": "15.0.1.0.1",
+    "version": "16.0.1.0.0",
     "category": "Sales",
     "license": "AGPL-3",
     "summary": "Adds start date and end date on sale order lines",
diff --git a/sale_start_end_dates/models/sale_order.py b/sale_start_end_dates/models/sale_order.py
index 3cda0109e3f..2803b37231e 100644
--- a/sale_start_end_dates/models/sale_order.py
+++ b/sale_start_end_dates/models/sale_order.py
@@ -160,12 +160,8 @@ def start_end_dates_product_id_change(self):
         if self.product_id.must_have_dates:
             if self.order_id.default_start_date:
                 self.start_date = self.order_id.default_start_date
-            else:
-                self.start_date = False
             if self.order_id.default_end_date:
                 self.end_date = self.order_id.default_end_date
-            else:
-                self.end_date = False
         else:
             self.start_date = False
             self.end_date = False
diff --git a/sale_start_end_dates/tests/test_sale_start_end_dates.py b/sale_start_end_dates/tests/test_sale_start_end_dates.py
index 6eff08c5ae0..fec6a520fb6 100644
--- a/sale_start_end_dates/tests/test_sale_start_end_dates.py
+++ b/sale_start_end_dates/tests/test_sale_start_end_dates.py
@@ -67,6 +67,8 @@ def test_start_end_dates_product_id_change(self):
             self.so.order_line.start_end_dates_product_id_change()
             self.so.order_line.start_date_change()
             self.so.order_line.end_date_change()
+        self.product_id.must_have_dates = False
+        self.so.order_line.start_end_dates_product_id_change()
 
     def test_start_end_dates_product_id(self):
         self.product_id.must_have_dates = False
@@ -112,3 +114,13 @@ def test_inverse_number_of_days(self):
         self.assertEqual(
             self.so.order_line[0].start_date, self.so.order_line[0].end_date
         )
+        self.so.order_line[0].number_of_days = -1
+        self.assertEqual(self.so.order_line[0].number_of_days, 1)
+
+    def test_prepare_invoice_line(self):
+        invoice_line_vals = self.so.order_line._prepare_invoice_line()
+        self.assertEqual(invoice_line_vals["product_id"], self.product_id.id)
+        self.assertEqual(
+            invoice_line_vals["start_date"], self.so.order_line[0].start_date
+        )
+        self.assertEqual(invoice_line_vals["end_date"], self.so.order_line[0].end_date)