diff --git a/Graphs/graphdata_custom.cpp b/Graphs/graphdata_custom.cpp
index a1d0dbce..f4df0d20 100644
--- a/Graphs/graphdata_custom.cpp
+++ b/Graphs/graphdata_custom.cpp
@@ -400,12 +400,15 @@ void HistoryData::Reload(Day *day)
         for (vector<Day *>::iterator dd=daylist.begin(); dd!=daylist.end(); dd++) { // average any multiple data sets
             Day *d=(*dd);
             if (d->machine_type()==MT_CPAP) {
-                y=Calc(d);
+                y+=Calc(d);
                 z++;
             }
         }
-        if (!z) continue;
-        if (z>1) y /= z;
+
+        if (!z)
+            continue;
+        if (z>1)
+            y /= z;
         if (first) {
           //  max_x=min_x=x;
             lasty=max_y=min_y=y;
@@ -443,6 +446,7 @@ void HistoryData::Reload(Day *day)
             max_y++;
         }
     }
+   // assert(max_y<10000000);
     real_min_y=min_y;
     real_max_y=max_y;
     m_ready=true;
diff --git a/SleepLib/loader_plugins/resmed_loader.cpp b/SleepLib/loader_plugins/resmed_loader.cpp
index da11ecdb..96d11ec4 100644
--- a/SleepLib/loader_plugins/resmed_loader.cpp
+++ b/SleepLib/loader_plugins/resmed_loader.cpp
@@ -357,14 +357,18 @@ bool ResmedLoader::LoadEVE(Session *sess,EDFParser &edf)
     //Event *e;
     for (int s=0;s<edf.GetNumSignals();s++) {
         recs=edf.edfsignals[s]->nr*edf.GetNumDataRecords()*2;
-        totaldur=edf.GetNumDataRecords()*edf.GetDuration();
-        totaldur/=3600.0;
+
         if (!sess->first().isValid()) {
             sess->set_first(edf.startdate);
-            sess->set_last(edf.startdate.addMSecs(totaldur*1000.0));
-            sess->set_hours(totaldur/3600.0);
+
+            totaldur=edf.GetNumDataRecords()*edf.GetDuration();
+            if (totaldur>0) {
+                sess->set_last(edf.startdate.addMSecs(totaldur*1000.0));
+                sess->set_hours(totaldur/3600.0);
+            }
         }
 
+//        totaldur/=3600.0;
         //t.sprintf("EVE: %li %.2f",recs,totaldur);
         //qDebug() << edf.edfsignals[s]->label << " " << t;
         data=(char *)edf.edfsignals[s]->data;
diff --git a/SleepLib/session.cpp b/SleepLib/session.cpp
index 0a9887be..15da75fb 100644
--- a/SleepLib/session.cpp
+++ b/SleepLib/session.cpp
@@ -179,7 +179,7 @@ double Session::weighted_avg_event_field(MachineCode mc,int field)
     //double hours=total.GetSeconds().GetLo()/3600.0;
 
     double s0=0,s1=0,s2=0;
-
+    if (total==0) return 0;
     for (int i=0; i<max_slots; i++) {
         if (vtime[i] > 0) {
             s0=(vtime[i]/3600.0);
@@ -188,7 +188,7 @@ double Session::weighted_avg_event_field(MachineCode mc,int field)
         }
     }
 
-    return (s1/hours())/mult;
+    return (s1/total)/mult;
 }
 
 void Session::AddEvent(Event * e)
diff --git a/SleepLib/session.h b/SleepLib/session.h
index ef706d13..ad51ade9 100644
--- a/SleepLib/session.h
+++ b/SleepLib/session.h
@@ -66,6 +66,9 @@ public:
         s_last=d;
     };
     void set_hours(float h) {
+        if (h<=0) {
+            h=0.000001;
+        }
         s_hours=h;
     };
 
diff --git a/overview.cpp b/overview.cpp
index 60c9d6ba..e6ee843a 100644
--- a/overview.cpp
+++ b/overview.cpp
@@ -45,7 +45,7 @@ Overview::Overview(QWidget *parent,QGLContext *context) :
     gSplitter->setHandleWidth(3);
     ui->graphLayout->addWidget(gSplitter);
 
-    AHI=new gGraphWindow(ui->SummaryGraphWindow,tr("AHI"),(QGLWidget *)NULL); // Not sure here..
+    AddGraph(AHI=new gGraphWindow(ui->SummaryGraphWindow,tr("AHI"),(QGLWidget *)NULL));
     AHI->SetTopMargin(10);
     AHI->SetBottomMargin(AHI->GetBottomMargin()+gXAxis::Margin+25);
     AHI->AddLayer(new gFooBar(7));
@@ -53,7 +53,7 @@ Overview::Overview(QWidget *parent,QGLContext *context) :
     AHI->AddLayer(new gBarChart(ahidata,QColor("red")));
     AHI->setMinimumHeight(170);
 
-    PRESSURE=new gGraphWindow(ui->SummaryGraphWindow,tr("Pressure"),AHI);
+    AddGraph(PRESSURE=new gGraphWindow(ui->SummaryGraphWindow,tr("Pressure"),AHI));
     //PRESSURE->SetMargins(10,15,65,80);
     PRESSURE->AddLayer(new gYAxis());
     PRESSURE->AddLayer(new gXAxis());
@@ -66,7 +66,7 @@ Overview::Overview(QWidget *parent,QGLContext *context) :
     PRESSURE->SetBottomMargin(PRESSURE->GetBottomMargin()+25);
     PRESSURE->setMinimumHeight(170);
 
-    LEAK=new gGraphWindow(ui->SummaryGraphWindow,tr("Leak"),AHI);
+    AddGraph(LEAK=new gGraphWindow(ui->SummaryGraphWindow,tr("Leak"),AHI));
     //LEAK->SetMargins(10,15,65,80);
     //LEAK->AddLayer(new gBarChart(leak,wxYELLOW));
     LEAK->AddLayer(new gXAxis());
@@ -76,7 +76,7 @@ Overview::Overview(QWidget *parent,QGLContext *context) :
     LEAK->SetBottomMargin(LEAK->GetBottomMargin()+25);
     LEAK->setMinimumHeight(170);
 
-    USAGE=new gGraphWindow(ui->SummaryGraphWindow,tr("Usage (Hours)"),AHI);
+    AddGraph(USAGE=new gGraphWindow(ui->SummaryGraphWindow,tr("Usage (Hours)"),AHI));
     //USAGE->SetMargins(10,15,65,80);
     USAGE->AddLayer(new gFooBar(7));
     USAGE->AddLayer(new gYAxis());
@@ -114,7 +114,12 @@ Overview::~Overview()
     delete dummyday;
     delete ui;
 }
-
+void Overview::RedrawGraphs()
+{
+    for (list<gGraphWindow *>::iterator g=Graphs.begin();g!=Graphs.end();g++) {
+        (*g)->updateGL();
+    }
+}
 void Overview::ReloadGraphs()
 {
     for (list<HistoryData *>::iterator h=Data.begin();h!=Data.end();h++) {
@@ -124,6 +129,7 @@ void Overview::ReloadGraphs()
     }
     on_rbLastWeek_clicked();
 }
+
 void Overview::UpdateGraphs()
 {
     QDate first=ui->drStart->date();
@@ -131,8 +137,8 @@ void Overview::UpdateGraphs()
     for (list<HistoryData *>::iterator h=Data.begin();h!=Data.end();h++) {
           //(*h)->Update(dummyday);
           (*h)->SetDateRange(first,last);
-      }
-
+    }
+    RedrawGraphs();
 }
 
 
diff --git a/overview.h b/overview.h
index 8f57aece..16b90b2f 100644
--- a/overview.h
+++ b/overview.h
@@ -51,6 +51,8 @@ private:
     QGLContext *shared_context;
 
     void AddData(HistoryData *d) { Data.push_back(d);  };
+    void AddGraph(gGraphWindow *w) { Graphs.push_back(w); };
+    void RedrawGraphs();
 
     HistoryData *ahidata,*pressure,*leak,*usage,*bedtime,*waketime,*pressure_iap,*pressure_eap;
     HistoryData *pressure_min,*pressure_max;
@@ -60,6 +62,7 @@ private:
     gLayer *prmax,*prmin,*iap,*eap,*pr;
 
     list<HistoryData *> Data;
+    list<gGraphWindow *> Graphs;
     Day *dummyday;
     QSplitter *gSplitter;
 };