diff --git a/power/ReadVcdActivities.cc b/power/ReadVcdActivities.cc
index 8763e0ff..853ef7bd 100644
--- a/power/ReadVcdActivities.cc
+++ b/power/ReadVcdActivities.cc
@@ -180,6 +180,7 @@ ReadVcdActivities::setVarActivity(const char *pin_name,
 {
   const Pin *pin = sdc_network_->findPin(pin_name);
   if (pin) {
+    debugPrint(debug_, "read_vcd_activities", 3, "%s values", pin_name);
     double transition_count, activity, duty;
     findVarActivity(var_values, value_bit,
                     transition_count, activity, duty);
@@ -205,16 +206,13 @@ ReadVcdActivities::findVarActivity(const VcdValues &var_values,
                                    double &duty)
 {
   transition_count = 0.0;
-  char prev_value = var_values[0].value();
+  char prev_value = var_values[0].value(value_bit);
   VcdTime prev_time = var_values[0].time();
   VcdTime high_time = 0;
   for (const VcdValue &var_value : var_values) {
     VcdTime time = var_value.time();
-    char value = var_value.value();
-    if (value == '\0') {
-      uint64_t bus_value = var_value.busValue();
-      value = ((bus_value >> value_bit) & 0x1) ? '1' : '0';
-    }
+    char value = var_value.value(value_bit);
+    debugPrint(debug_, "read_vcd_activities", 3, " %llu %c", time, value);
     if (prev_value == '1')
       high_time += time - prev_time;
     if (value != prev_value)
diff --git a/power/Vcd.cc b/power/Vcd.cc
index 1ea9d8c3..a140528c 100644
--- a/power/Vcd.cc
+++ b/power/Vcd.cc
@@ -201,4 +201,13 @@ VcdValue::VcdValue(VcdTime time,
 {
 }
 
+char
+VcdValue::value(int value_bit) const
+{
+  if (value_ == '\0')
+    return ((bus_value_ >> value_bit) & 0x1) ? '1' : '0';
+  else
+    return value_;
+}
+
 }
diff --git a/power/Vcd.hh b/power/Vcd.hh
index 76d904b5..b61d3935 100644
--- a/power/Vcd.hh
+++ b/power/Vcd.hh
@@ -146,6 +146,7 @@ public:
   VcdTime time() const { return time_; }
   char value() const { return value_; }
   uint64_t busValue() const { return bus_value_; }
+  char value(int value_bit) const;
 
 private:
   VcdTime time_;