diff --git a/mcm/json_layer/chained_request.py b/mcm/json_layer/chained_request.py
index cc1c01c9..b732e1ce 100644
--- a/mcm/json_layer/chained_request.py
+++ b/mcm/json_layer/chained_request.py
@@ -450,7 +450,25 @@ def flow_to_next_step(self, input_dataset='', block_black_list=None, block_white
         #current_campaign -> next_campaign
 
         ##determine whether we have an input dataset for the next request
-        if len(current_request.get_attribute('reqmgr_name')):
+        if len(current_request.get_attribute('output_dataset')):
+            input_dataset = current_request.get_attribute('output_dataset')[-1]
+            
+            if "use_datatier" in mcm_f.get_attribute('request_parameters'):
+                ## N.B. this does not function for TaskChain handling without further development
+                use_datatier=mcm_f.get_attribute('request_parameters')["use_datatier"]
+                outputs=current_request.get_attribute('output_dataset')
+                possible = filter(lambda ds : ds.split('/')[-1] == use_datatier, outputs)
+                if len(possible)!=0:
+                    raise self.ChainedRequestCannotFlowException(self.get_attribute('_id'),
+                                                                 "There isn't a possible corresponding output datatiers (%s) for the requested datatier (%s)" %( map(lambda ds : ds.split('/')[-1], outputs),
+                                                                                                                                                                 use_datatier,
+                                                                                                                                                                 ))
+                
+                else:
+                    input_dataset = possible[0]
+
+        elif len(current_request.get_attribute('reqmgr_name')):
+            ## the later check pre-dates the inclusion of output_dataset as a member of request object
             last_wma = current_request.get_attribute('reqmgr_name')[-1]
             if 'content' in last_wma and 'pdmv_dataset_name' in last_wma['content']:
                 input_dataset = last_wma['content']['pdmv_dataset_name']
diff --git a/mcm/json_layer/request.py b/mcm/json_layer/request.py
index c498553c..9f1f05b2 100644
--- a/mcm/json_layer/request.py
+++ b/mcm/json_layer/request.py
@@ -757,9 +757,10 @@ def get_tier(self,i):
         tiers = s['datatier']
         if isinstance(tiers, str):
             tiers = tiers.split(',')
-        return tiers
+        return reversed(tiers)
 
     def get_tiers(self):
+        ## the output is an ordered list of tiers, the last item being the main produced tiers
         r_tiers=[]
         keeps = self.get_attribute('keep_output')
         for (i, s) in enumerate(self.get_attribute('sequences')):
@@ -1538,7 +1539,14 @@ def inspect_submitted(self):
                                 'message' : 'No output dataset have been recognized'})
                         saved = db.save(self.json())
                         return not_good
-                    ds_for_accounting = collected[0]
+                    ## order according the expected tiers : the last is the more important
+                    ## does not function if two output of the same tier are expected
+                    recollected=[]
+                    for tier in tiers_expected:
+                        recollected.extend( filter( lambda dn : dn.split('/')[-1]==tier, collected) )
+                    collected=recollected
+
+                    ds_for_accounting = collected[-1] ## the last one if the one of importance
                     if not 'pdmv_dataset_statuses' in wma_r_N['content'] or not ds_for_accounting in wma_r_N['content']['pdmv_dataset_statuses']:
                         counted = wma_r_N['content']['pdmv_evts_in_DAS']+ wma_r_N['content']['pdmv_open_evts_in_DAS']
                         if not counted:
diff --git a/mcm/rest_api/ChainedRequestActions.py b/mcm/rest_api/ChainedRequestActions.py
index a66a1208..e8eee63b 100644
--- a/mcm/rest_api/ChainedRequestActions.py
+++ b/mcm/rest_api/ChainedRequestActions.py
@@ -650,7 +650,17 @@ def request_to_tasks( r , base, depend):
                     task_dict.update({"SplittingAlgo"  : "EventAwareLumiBased",
                                       "InputFromOutputModule" : ts[-1]['output_'],
                                       "InputTask" : ts[-1]['TaskName']})
+                    
                 task_dict['output_'] = "%soutput"%(r.get_attribute('sequences')[si]['eventcontent'][0])
+                task_dict['datatiers_'] = r.get_attribute('sequences')[si]['datatier']
+                task_dict['outputs_'] = ["%soutput"%(ec) for ec in r.get_attribute('sequences')[si]['eventcontent']]
+                task_dict['use_datatier_']=None
+                if r.get_attribute('flown_with'):
+                    fdb = database('flows')
+                    f = fdb.get( r.get_attribute('flown_with') )
+                    if "use_datatier" in f["request_parameters"]:
+                        task_dict['use_datatier_']=f["request_parameters"]["use_datatier"]
+
                 task_dict['priority_'] = r.get_attribute('priority')
                 task_dict['request_type_'] = r.get_wmagent_type()
                 ts.append(task_dict)    
@@ -704,9 +714,14 @@ def request_to_tasks( r , base, depend):
 
         for (r,item) in tasktree.items():
             for n in item['next']:
+                ## do the connecting of tasks outputs
                 tasktree[n]['dict'][0].update({"InputFromOutputModule" : item['dict'][-1]['output_'],
-                                                       "InputTask" : item['dict'][-1]['TaskName']})
-        
+                                               "InputTask" : item['dict'][-1]['TaskName']})
+                ## do a special treatment if the flow was requested to use a specific datatier
+                if tasktree[n]['dict'][0]['use_datatier_']:
+                    use_datatier=tasktree[n]['dict'][0]['use_datatier_']
+                    index_datatier=item['dict'][-1]['datatiers_'].index(use_datatier)
+                    tasktree[n]['dict'][0]["InputFromOutputModule"] = item['dict'][-1]['outputs_'[index_datatier]
 
         wma={
             "RequestType" : "TaskChain",