diff --git a/neat/globals/manager.py b/neat/globals/manager.py
index 1512c10..c2f699d 100644
--- a/neat/globals/manager.py
+++ b/neat/globals/manager.py
@@ -310,10 +310,11 @@ def execute_underload(config, state, host):
         vm_placement_params = common.parse_parameters(
             config['algorithm_vm_placement_parameters'])
         vm_placement_state = None
-        vm_placement = config['algorithm_vm_placement_factory'](
-            time_step,
-            migration_time,
-            vm_placement_params)
+        vm_placement = common.call_function_by_name(
+            config['algorithm_vm_placement_factory'],
+            [time_step,
+             migration_time,
+             vm_placement_params])
         state['vm_placement'] = vm_placement
         state['vm_placement_state'] = {}
     else:
@@ -491,10 +492,11 @@ def execute_overload(config, state, vm_uuids):
         vm_placement_params = json.loads(
             config['algorithm_vm_placement_params'])
         vm_placement_state = None
-        vm_placement = config['algorithm_vm_placement_factory'](
-            time_step,
-            migration_time,
-            vm_placement_params)
+        vm_placement = common.call_function_by_name(
+            config['algorithm_vm_placement_factory'],
+            [time_step,
+             migration_time,
+             vm_placement_params])
         state['vm_placement'] = vm_placement
     else:
         vm_placement = state['vm_placement']
diff --git a/neat/globals/vm_placement/bin_packing.py b/neat/globals/vm_placement/bin_packing.py
index 2205072..3b68a4c 100644
--- a/neat/globals/vm_placement/bin_packing.py
+++ b/neat/globals/vm_placement/bin_packing.py
@@ -30,7 +30,7 @@ def best_fit_decreasing_factory(time_step, migration_time, params):
      :type time_step: int,>=0
 
     :param migration_time: The VM migration time in time seconds.
-     :type migration_time: int,>=0
+     :type migration_time: float,>=0
 
     :param params: A dictionary containing the algorithm's parameters.
      :type params: dict(str: *)
diff --git a/tests/globals/vm_placement/test_bin_packing.py b/tests/globals/vm_placement/test_bin_packing.py
index b788f17..89feffb 100644
--- a/tests/globals/vm_placement/test_bin_packing.py
+++ b/tests/globals/vm_placement/test_bin_packing.py
@@ -24,7 +24,7 @@ logging.disable(logging.CRITICAL)
 class BinPacking(TestCase):
 
     def test_best_fit_decreasing_factory(self):
-        alg = packing.best_fit_decreasing_factory(300, 20,
+        alg = packing.best_fit_decreasing_factory(300, 20.,
                                                   {'cpu_threshold': 0.8,
                                                    'ram_threshold': 0.9})