diff --git a/oswin_tempest_plugin/tests/_mixins/optional_feature.py b/oswin_tempest_plugin/tests/_mixins/optional_feature.py
index 0ad83b4..9a5189b 100644
--- a/oswin_tempest_plugin/tests/_mixins/optional_feature.py
+++ b/oswin_tempest_plugin/tests/_mixins/optional_feature.py
@@ -38,7 +38,8 @@ class _OptionalFeatureMixin(resize._ResizeUtils):
     turning on / off the optional feature), and check its network
     connectivity.
 
-    The optional feature flavor is based on the configured compute.flavor_ref,
+    The optional feature flavor is based on the test suite's configured
+    _FLAVOR_REF (typically compute.flavor_ref or compute.flavor_ref_alt),
     with some updates. For example, if the vNUMA configuration is to be tested,
     the new flavor would contain the flavor extra_spec {'hw:numa_nodes="1"'}.
     Keep in mind that all the extra_spec keys and values have to be strings.
@@ -55,8 +56,8 @@ class _OptionalFeatureMixin(resize._ResizeUtils):
     def _get_flavor_ref(self):
         """Gets a new optional feature flavor ref.
 
-        Creates a new flavor based on the configured flavor_ref, with some
-        updates specific to the optional feature.
+        Creates a new flavor based on the test suite's configured _FLAVOR_REF,
+        with some updates specific to the optional feature.
 
         :returns: nova flavor ID.
         """
@@ -64,7 +65,7 @@ class _OptionalFeatureMixin(resize._ResizeUtils):
         # _create_server will call this method to get the flavor reference
         # needed to spawn a new instance. Thus, any other test will spawn
         # instances with this Optional Feature.
-        new_flavor = self._create_new_flavor(CONF.compute.flavor_ref,
+        new_flavor = self._create_new_flavor(self._FLAVOR_REF,
                                              self._FEATURE_FLAVOR)
         return new_flavor['id']
 
@@ -75,18 +76,15 @@ class _OptionalFeatureMixin(resize._ResizeUtils):
     @testtools.skipUnless(CONF.compute_feature_enabled.resize,
                           'Resize is not available.')
     def test_resize_add_feature(self):
-        new_flavor = self._create_new_flavor(CONF.compute.flavor_ref,
-                                             self._FEATURE_FLAVOR)
-        server_tuple = self._create_server(CONF.compute.flavor_ref)
-        self._resize_server(server_tuple, new_flavor['id'])
+        new_flavor = self._get_flavor_ref()
+        server_tuple = self._create_server(self._FLAVOR_REF)
+        self._resize_server(server_tuple, new_flavor)
         self._check_server_connectivity(server_tuple)
 
     @testtools.skipUnless(CONF.compute_feature_enabled.resize,
                           'Resize is not available.')
     def test_resize_remove_feature(self):
-        new_flavor = self._create_new_flavor(CONF.compute.flavor_ref,
-                                             self._FEATURE_FLAVOR)
-        vanilla_flavor = CONF.compute.flavor_ref
-        server_tuple = self._create_server(new_flavor['id'])
+        vanilla_flavor = self._FLAVOR_REF
+        server_tuple = self._create_server()
         self._resize_server(server_tuple, vanilla_flavor)
         self._check_server_connectivity(server_tuple)
diff --git a/oswin_tempest_plugin/tests/_mixins/resize.py b/oswin_tempest_plugin/tests/_mixins/resize.py
index 91fa86b..60ab746 100644
--- a/oswin_tempest_plugin/tests/_mixins/resize.py
+++ b/oswin_tempest_plugin/tests/_mixins/resize.py
@@ -70,7 +70,8 @@ class _ResizeMixin(_ResizeUtils):
     This mixin will add cold resize tests. The tests will create a new
     instance, resize it to a new flavor, and check its network connectivity.
 
-    The new flavor is based on the configured compute.flavor_ref, with some
+    The new flavor is based on the test suite's configured _FLAVOR_REF (
+    typically compute.flavor_ref or compute.flavor_ref_alt), with some
     updates. For example, if the vNUMA configuration is to be tested, the new
     flavor would contain the flavor extra_spec 'hw:numa_nodes=1'.
     """
diff --git a/oswin_tempest_plugin/tests/test_base.py b/oswin_tempest_plugin/tests/test_base.py
index bda6c93..7999742 100644
--- a/oswin_tempest_plugin/tests/test_base.py
+++ b/oswin_tempest_plugin/tests/test_base.py
@@ -161,7 +161,7 @@ class TestBase(tempest.test.BaseTestCase):
         clients = self.os_primary
         name = data_utils.rand_name(self.__class__.__name__ + "-server")
         image_id = self._get_image_ref()
-        flavor = flavor or self._FLAVOR_REF or self._get_flavor_ref()
+        flavor = flavor or self._get_flavor_ref()
         keypair = self.create_keypair()
         tenant_network = self.get_tenant_network()
         security_group = self._create_security_group()