diff --git a/include/mcc/mcc_keyvalue.h b/include/mcc/mcc_keyvalue.h
index ca84f12..418f7b5 100644
--- a/include/mcc/mcc_keyvalue.h
+++ b/include/mcc/mcc_keyvalue.h
@@ -137,12 +137,7 @@ public:
 
     static constexpr size_t NUMBER_OF_RECORDS = std::tuple_size_v<DESCR_T>;
 
-    MccKeyValueHolder(DESCR_T desc)
-        : _keyValue(desc), _mapHash{[&desc]<size_t... Is>(std::index_sequence<Is...>) {
-              auto arr = std::array{std::make_pair(utils::FNV1aHash(std::get<Is>(desc).key), Is)...};
-              std::sort(arr.begin(), arr.end(), [](auto const& p1, auto const& p2) { return p1.first < p2.first; });
-              return arr;
-          }(std::make_index_sequence<NUMBER_OF_RECORDS>())}
+    MccKeyValueHolder(DESCR_T desc) : _keyValue(desc)
     {
         [this]<size_t... I>(std::index_sequence<I...>) {
             ((_hashes[I] = utils::FNV1aHash(std::get<I>(_keyValue).key)), ...);
@@ -151,6 +146,29 @@ public:
         _changedKey.insert_range(_hashes);
     }
 
+    MccKeyValueHolder(MccKeyValueHolder const& other) : MccKeyValueHolder(other._keyValue)
+    {
+        copyInst(other);
+    };
+
+    MccKeyValueHolder(MccKeyValueHolder&& other)
+    {
+        moveInst(std::move(other));
+    };
+
+    MccKeyValueHolder& operator=(MccKeyValueHolder const& other)
+    {
+        copyInst(other);
+
+        return *this;
+    };
+
+    MccKeyValueHolder& operator=(MccKeyValueHolder&& other)
+    {
+        moveInst(std::move(other));
+
+        return *this;
+    };
 
     constexpr std::array<std::string_view, NUMBER_OF_RECORDS> keys() const
     {
@@ -463,8 +481,6 @@ protected:
     std::unordered_map<size_t, std::string> _inlineComment{};  // inline (after key=value pair) comment
     std::unordered_set<size_t> _changedKey{};                  // loaded keys (see fromCharRange)
 
-    const std::array<std::pair<size_t, size_t>, NUMBER_OF_RECORDS> _mapHash;
-
     //
     //  NOTE: deduced this is needed here to use "forKey" method in getter and setter (const and non-const contexts)!!!
     //
@@ -540,6 +556,57 @@ protected:
 
         return MccKeyValueHolderErrorCode::ERROR_OK;
     }
+
+
+    template <size_t I = 0>
+    void copyInst(MccKeyValueHolder const& other)
+    {
+        if constexpr (I < NUMBER_OF_RECORDS) {
+            // here one needs check equality of the keys!!!
+            if (_hashes[I] == other._hashes[I]) {
+                auto& orec = std::get<I>(other._keyValue);
+                std::get<I>(_keyValue).value = orec.value;
+                std::get<I>(_keyValue).default_value = orec.default_value;
+                std::get<I>(_keyValue).serial_pars = orec.serial_pars;
+
+                if (auto it = other._headComment.find(_hashes[I]); it != other._headComment.end()) {
+                    _headComment[_hashes[I]] = it->second;
+                }
+                if (auto it = other._inlineComment.find(_hashes[I]); it != other._inlineComment.end()) {
+                    _inlineComment[_hashes[I]] = it->second;
+                }
+
+                _changedKey.insert(_hashes[I]);
+            }
+
+            copyInst<I + 1>(other);
+        }
+    }
+
+    template <size_t I = 0>
+    void moveInst(MccKeyValueHolder&& other)
+    {
+        if constexpr (I < NUMBER_OF_RECORDS) {
+            // here one needs check equality of the keys!!!
+            if (_hashes[I] == other._hashes[I]) {
+                auto& orec = std::get<I>(other._keyValue);
+                std::get<I>(_keyValue).value = std::move(orec.value);
+                std::get<I>(_keyValue).default_value = std::move(orec.default_value);
+                std::get<I>(_keyValue).serial_pars = std::move(orec.serial_pars);
+
+                if (auto it = other._headComment.find(_hashes[I]); it != other._headComment.end()) {
+                    _headComment[_hashes[I]] = std::move(it->second);
+                }
+                if (auto it = other._inlineComment.find(_hashes[I]); it != other._inlineComment.end()) {
+                    _inlineComment[_hashes[I]] = std::move(it->second);
+                }
+
+                _changedKey.insert(_hashes[I]);
+            }
+
+            moveInst<I + 1>(other);
+        }
+    }
 };
 
 template <mcc_record_value_c T>
diff --git a/include/mcc/mcc_pzone.h b/include/mcc/mcc_pzone.h
index e089524..18eef99 100644
--- a/include/mcc/mcc_pzone.h
+++ b/include/mcc/mcc_pzone.h
@@ -352,6 +352,7 @@ protected:
     }
 };
 
+static_assert(std::is_copy_assignable_v<MccAltLimitPZ<MccAltLimitKind::MIN_ALT_LIMIT>>);
 
 /*
     to be serialized in format:
@@ -589,14 +590,32 @@ protected:
             coords.to(xy);
         }
 
-        double x = xy.x();
-
         if constexpr (AXIS_KIND == MccCoordKind::COORDS_KIND_HA_OBS) {
+            double x = xy.x();
+
             if (from_time) {                                            // timeFromPZone
                 time_ang = (_minLimit - x) / MCC_SIDERAL_TO_UT1_RATIO;  // to UT1 scale
             } else {                                                    // timeToPZone
                 time_ang = (_maxLimit - x) / MCC_SIDERAL_TO_UT1_RATIO;  // to UT1 scale
             }
+        } else if constexpr (AXIS_KIND == MccCoordKind::COORDS_KIND_DEC_OBS) {
+            double y = xy.y();
+
+            // TODO: !!!!!!!!!!!!!!!!!!!!!!!!
+            // assume here sideral speed moving! so, observed DEC is near constant
+            if (from_time) {  // timeFromPZone
+                if (y < _minLimit || y > _maxLimit) {
+                    time_ang = std::numeric_limits<double>::max();
+                } else {
+                    time_ang = 0;
+                }
+            } else {                                   // timeToPZone
+                if (y < _minLimit || y > _maxLimit) {  // already in the zone
+                    time_ang = 0;
+                } else {
+                    time_ang = std::numeric_limits<double>::max();
+                }
+            }
         } else if constexpr (AXIS_KIND == MccCoordKind::COORDS_KIND_AZ) {
             static_assert(false, "NOT IMPLEMENTED YET!!!");
         } else {
@@ -613,6 +632,8 @@ protected:
     }
 };
 
+static_assert(std::is_copy_assignable_v<MccAxisLimitSwitchPZ<MccCoordKind::COORDS_KIND_HA_OBS>>);
+static_assert(std::is_copy_assignable_v<MccAxisLimitSwitchPZ<MccCoordKind::COORDS_KIND_DEC_OBS>>);
 
 /*
     to be serialized in format: