diff --git a/addons/project/project.py b/addons/project/project.py
index 3319bd1e571..206c6e5851b 100644
--- a/addons/project/project.py
+++ b/addons/project/project.py
@@ -289,12 +289,12 @@ class task(osv.osv):
         'history': fields.function(_history_get, method=True, string="Task Details", type="text"),
         'notes': fields.text('Notes'),
 
-        'planned_hours': fields.float('Planned Hours', readonly=True, states={'draft':[('readonly',False)]}, required=True),
-        'effective_hours': fields.function(_hours_get, method=True, string='Hours Spent', multi='hours', store=True),
-        'remaining_hours': fields.float('Remaining Hours', digits=(16,2)),
-        'total_hours': fields.function(_hours_get, method=True, string='Total Hours', multi='hours', store=True),
-        'progress': fields.function(_hours_get, method=True, string='Progress (%)', multi='hours', store=True),
-        'delay_hours': fields.function(_hours_get, method=True, string='Delay Hours', multi='hours', store=True),
+        'planned_hours': fields.float('Planned Hours', readonly=True, states={'draft':[('readonly',False)]}, required=True, 'Estimated time to do the task, usually set by the project manager when the task is in draft state.'),
+        'effective_hours': fields.function(_hours_get, method=True, string='Hours Spent', multi='hours', store=True, help="Computed using the sum of the task work done."),
+        'remaining_hours': fields.float('Remaining Hours', digits=(16,2), help="Total remaining time, can be re-estimated periodically by the assignee of the task."),
+        'total_hours': fields.function(_hours_get, method=True, string='Total Hours', multi='hours', store=True, help="Computed as: Time Spent + Remaining Time."),
+        'progress': fields.function(_hours_get, method=True, string='Progress (%)', multi='hours', store=True, help="Computed as: Time Spent / Total Time."),
+        'delay_hours': fields.function(_hours_get, method=True, string='Delay Hours', multi='hours', store=True, help="Computed as: Total Time - Estimated Time. It gives the difference of the time estimated by the project manager and the real time to close the task."),
 
         'user_id': fields.many2one('res.users', 'Assigned to'),
         'partner_id': fields.many2one('res.partner', 'Partner'),
diff --git a/addons/project/project_view.xml b/addons/project/project_view.xml
index 45db7cee9dd..45a0256c05a 100644
--- a/addons/project/project_view.xml
+++ b/addons/project/project_view.xml
@@ -54,7 +54,7 @@
                             <field name="warn_header" nolabel="1" colspan="2"/>
                             <field name="warn_footer" nolabel="1" colspan="2"/>
                             <group col="3" colspan="4">
-                                <separator string="Automatic variables you can use, use exactly the same form" colspan="4"/>
+                                <separator string="Automatic variables for headers and footer. Use exactly the same notation." colspan="4"/>
                                 <label string="Task: %%(name)s"/>
                                 <label string="User: %%(user_id)s"/>
                                 <label string="ID: %%(task_id)s"/>