diff --git a/libraries/chain/db_maint.cpp b/libraries/chain/db_maint.cpp
index 5d973a09..929346b9 100644
--- a/libraries/chain/db_maint.cpp
+++ b/libraries/chain/db_maint.cpp
@@ -165,6 +165,20 @@ void database::pay_sons()
    }
 }
 
+void database::update_son_metrics()
+{
+   const auto& son_idx = get_index_type<son_index>().indices().get< by_id >();
+   for( auto& son : son_idx )
+   {
+      auto& stats = son.statistics(*this);
+      modify( stats, [&]( son_statistics_object& _stats)
+      {
+         _stats.total_downtime += _stats.current_interval_downtime;
+         _stats.current_interval_downtime = 0;
+      });
+   }
+}
+
 void database::pay_workers( share_type& budget )
 {
 //   ilog("Processing payroll! Available budget is ${b}", ("b", budget));
@@ -542,6 +556,8 @@ void database::update_active_sons()
       _sso.scheduler.update(active_sons);
    });
 
+   update_son_metrics();
+
    if(gpo.active_sons.size() > 0 ) {
       if(gpo.parameters.get_son_btc_account_id() == GRAPHENE_NULL_ACCOUNT) {
          const auto& son_btc_account = create<account_object>( [&]( account_object& obj ) {
diff --git a/libraries/chain/include/graphene/chain/database.hpp b/libraries/chain/include/graphene/chain/database.hpp
index 56a62577..ea2ccffd 100644
--- a/libraries/chain/include/graphene/chain/database.hpp
+++ b/libraries/chain/include/graphene/chain/database.hpp
@@ -548,6 +548,7 @@ namespace graphene { namespace chain {
          void perform_chain_maintenance(const signed_block& next_block, const global_property_object& global_props);
          void update_active_witnesses();
          void update_active_committee_members();
+         void update_son_metrics();
          void update_active_sons();
          void update_worker_votes();
       
diff --git a/libraries/chain/son_evaluator.cpp b/libraries/chain/son_evaluator.cpp
index 34f4daa3..79660921 100644
--- a/libraries/chain/son_evaluator.cpp
+++ b/libraries/chain/son_evaluator.cpp
@@ -165,6 +165,7 @@ object_id_type son_heartbeat_evaluator::do_apply(const son_heartbeat_operation&
 
 void_result son_report_down_evaluator::do_evaluate(const son_report_down_operation& op)
 { try {
+    FC_ASSERT(db().head_block_time() >= HARDFORK_SON_TIME, "Not allowed until SON HARDFORK"); // can be removed after HF date pass
     FC_ASSERT(op.payer == db().get_global_properties().parameters.get_son_btc_account_id(), "Payer should be the son btc account");
     const auto& idx = db().get_index_type<son_index>().indices().get<by_id>();
     FC_ASSERT( idx.find(op.son_id) != idx.end() );
diff --git a/libraries/plugins/peerplays_sidechain/peerplays_sidechain_plugin.cpp b/libraries/plugins/peerplays_sidechain/peerplays_sidechain_plugin.cpp
index 59ea5786..86caec2d 100644
--- a/libraries/plugins/peerplays_sidechain/peerplays_sidechain_plugin.cpp
+++ b/libraries/plugins/peerplays_sidechain/peerplays_sidechain_plugin.cpp
@@ -247,6 +247,7 @@ void peerplays_sidechain_plugin_impl::create_son_down_proposals()
 
    chain::database& d = plugin.database();
    const chain::global_property_object& gpo = d.get_global_properties();
+   const chain::dynamic_global_property_object& dgpo = d.get_dynamic_global_properties();
    const auto& idx = d.get_index_type<chain::son_index>().indices().get<by_id>();
    std::set<son_id_type> sons_being_reported_down = d.get_sons_being_reported_down();
    chain::son_id_type my_son_id = *(_sons.begin());
@@ -256,7 +257,8 @@ void peerplays_sidechain_plugin_impl::create_son_down_proposals()
       }
       auto son_obj = idx.find( son_inf.son_id );
       auto stats = son_obj->statistics(d);
-      fc::time_point_sec last_active_ts = stats.last_active_timestamp;
+      fc::time_point_sec last_maintenance_time = dgpo.next_maintenance_time - gpo.parameters.maintenance_interval;
+      fc::time_point_sec last_active_ts = ((stats.last_active_timestamp > last_maintenance_time) ? stats.last_active_timestamp : last_maintenance_time);
       int64_t down_threshold = 2*180000000;
       if(son_obj->status == chain::son_status::active && (fc::time_point::now() - last_active_ts) > fc::microseconds(down_threshold))  {
          ilog("peerplays_sidechain_plugin:  sending son down proposal for ${t} from ${s}",("t",std::string(object_id_type(son_obj->id)))("s",std::string(object_id_type(my_son_id))));