diff --git a/Code/Mantid/Testing/SystemTests/tests/analysis/EnginXCalibrateTest.py b/Code/Mantid/Testing/SystemTests/tests/analysis/EnginXCalibrateTest.py
index eae4d552dd9dc4a99b95c2765456e4df7b36db29..ac53f59b55c3a3e5d406354afe94ad8859b6298b 100644
--- a/Code/Mantid/Testing/SystemTests/tests/analysis/EnginXCalibrateTest.py
+++ b/Code/Mantid/Testing/SystemTests/tests/analysis/EnginXCalibrateTest.py
@@ -19,10 +19,7 @@ class EnginXCalibrateTest(stresstesting.MantidStressTest):
       if sys.platform == "darwin":
           # Mac fitting tests produce differences for some reason.
           self.assertDelta(self.difc, 18405.4, 0.1)
-          if int(platform.release().split('.')[0]) < 13:
-              self.assertDelta(self.zero, 3.53, 0.01)
-          else:
-              self.assertDelta(self.zero, 3.51, 0.01)
+          self.assertDelta(self.zero, 3.53, 0.05)
       else:
           self.assertDelta(self.difc, 18404.522, 0.001)
           self.assertDelta(self.zero, 4.426, 0.001)