diff --git a/cace/parameter/parameter.py b/cace/parameter/parameter.py
index d767d68..07cbc8e 100755
--- a/cace/parameter/parameter.py
+++ b/cace/parameter/parameter.py
@@ -327,7 +327,8 @@ def run(self):
             self.result_type = ResultType.ERROR
             self.canceled = True
 
-        self.evaluate_result()
+        if self.result_type != ResultType.SKIPPED:
+            self.evaluate_result()
 
         # Set done before calling end cb
         self.done = True
@@ -901,11 +902,19 @@ def makeplot(
             and not 'xaxis' in self.param['plot'][plot_name]
         ):
             err(f'Neither yaxis nor xaxis specified in plot {plot_name}.')
+            self.result_type = ResultType.ERROR
+            return None
 
         xvariable = None
         if 'xaxis' in self.param['plot'][plot_name]:
+
             xvariable = self.param['plot'][plot_name]['xaxis']
 
+            # Remove any bit slices
+            pmatch = self.vectrex.match(xvariable)
+            if pmatch:
+                xvariable = pmatch.group(1)
+
         xdisplay = xvariable
         xunit = ''
 
@@ -917,6 +926,12 @@ def makeplot(
             if not isinstance(yvariables, list):
                 yvariables = [yvariables]
 
+            for i, yvariable in enumerate(yvariables):
+                # Remove any bit slices
+                pmatch = self.vectrex.match(yvariable)
+                if pmatch:
+                    yvariables[i] = pmatch.group(1)
+
         ydisplays = {key: key for key in yvariables}
         yunits = {key: '' for key in yvariables}
 
@@ -1189,6 +1204,7 @@ def makeplot(
                     xvalues = conditions[xvariable].values
                 else:
                     err(f'Unknown variable: {xvariable} in plot {plot_name}.')
+                    self.result_type = ResultType.ERROR
                     return None
 
             xvalues_list.append(xvalues)
@@ -1206,6 +1222,7 @@ def makeplot(
                         err(
                             f'Unknown variable: {yvariable} in plot {plot_name}.'
                         )
+                        self.result_type = ResultType.ERROR
                         return None
 
             yvalues_list.append(yvalues)
@@ -1232,6 +1249,15 @@ def makeplot(
                 marker = 'o'
 
             for yvalue in yvalues:
+
+                # Check length of x and y
+                if len(xvalues) != len(yvalue):
+                    err(
+                        f'Length of x and y is not the same ({len(xvalues)}, {len(yvalue)}).'
+                    )
+                    self.result_type = ResultType.ERROR
+                    return None
+
                 self.plot(
                     xvalues,
                     yvalue,
@@ -1243,6 +1269,15 @@ def makeplot(
                 )
 
             if not yvalues:
+
+                # Check length of x and y
+                if len(xvalues) != len(yvalues):
+                    err(
+                        f'Length of x and y is not the same ({len(xvalues)}, {len(yvalues)}).'
+                    )
+                    self.result_type = ResultType.ERROR
+                    return None
+
                 self.plot(
                     xvalues,
                     yvalues,
diff --git a/cace/parameter/parameter_ngspice.py b/cace/parameter/parameter_ngspice.py
index 953a176..54d98a7 100755
--- a/cace/parameter/parameter_ngspice.py
+++ b/cace/parameter/parameter_ngspice.py
@@ -243,6 +243,12 @@ def implementation(self):
             # First remove the collate condition from the conditions
             if self.get_argument('collate'):
                 collate_variable = self.get_argument('collate')
+
+                # Remove any bit slices
+                pmatch = self.vectrex.match(collate_variable)
+                if pmatch:
+                    collate_variable = pmatch.group(1)
+
                 info(f'Collating results using condition "{collate_variable}"')
 
                 if collate_variable in conditions:
@@ -637,10 +643,13 @@ def implementation(self):
 
             dbg(f'collated values: {collated_values}')
 
+            # Put back the collate condition for script and plotting
             if self.get_argument('collate'):
-                condition_set[collate_variable] = collate_values
+                condition_sets[index][collate_variable] = collate_values
 
-                dbg(f'collated condition: {condition_set[collate_variable]}')
+                dbg(
+                    f'collated condition: {condition_sets[index][collate_variable]}'
+                )
 
             dbg(f'Extending final result…')
 
@@ -685,7 +694,7 @@ def write(self, text):
                             text = text.rstrip()
                             if len(text) == 0:
                                 return
-                            info(f'User script: {text}')
+                            info(text)
 
                         def flush(self):
                             self._stdout.flush()
@@ -694,26 +703,30 @@ def __getattr__(self, attr):
                             return getattr(self._stdout, attr)
 
                     with CustomPrint() as output:
-                        collated_values = user_script.postprocess(
+                        script_values = user_script.postprocess(
                             collated_values, condition_set
                         )
 
-                except Exception as e:
-                    err(f'Error in user script: {e}')
+                        # Merge collated and script variables
+                        collated_values.update(script_values)
+
+                except Exception:
+                    err(f'Error in user script:')
+                    traceback.print_exc()
                     self.result_type = ResultType.ERROR
                     return
 
             for variable in script_variables:
                 if variable != None:
                     # Check for variable in results
-                    if variable not in collated_values:
-                        err(f'Variable "{variable}" not in results.')
+                    if variable not in script_values:
+                        err(f'Variable "{variable}" not in script results.')
                         self.result_type = ResultType.ERROR
                         return
 
                     # Extend the final result
                     self.get_result(variable).values.extend(
-                        collated_values[variable]
+                        script_values[variable]
                     )
 
             simulation_values.append(collated_values)
@@ -722,6 +735,11 @@ def __getattr__(self, attr):
         dbg(f'simulation_values: {simulation_values}')
         dbg(f'results_dict: {self.results_dict}')
 
+        # Put back the collate_condition
+        # TODO find a better way
+        if self.get_argument('collate'):
+            conditions[collate_variable] = collate_condition
+
         # Create a plot if specified
         if 'plot' in self.param:
             # Create the plots and save them