diff --git a/asibfm700/asibfm700_configfile.h b/asibfm700/asibfm700_configfile.h
index 4988db7..b3521fc 100644
--- a/asibfm700/asibfm700_configfile.h
+++ b/asibfm700/asibfm700_configfile.h
@@ -129,6 +129,13 @@ public:
             }
 
             value = r;
+        } else if constexpr (mcc::traits::mcc_time_duration_c<value_t>) {
+            typename value_t::rep vd;
+
+            bool ok = self(str, vd);
+            if (ok) {
+                value = value_t{vd};
+            }
         } else {
             return false;
         }
@@ -231,8 +238,8 @@ public:
 
                 if constexpr (std::convertible_to<v_t, T>) {
                     res = static_cast<T>(std::forward<decltype(val)>(val));
-                } else if constexpr (std::constructible_from<T, v_t>) {
-                    res = T{std::forward<decltype(val)>(val)};
+                    // } else if constexpr (std::constructible_from<T, v_t>) {
+                    //     res = T{std::forward<decltype(val)>(val)};
                 } else {
                     res = std::unexpected(std::make_error_code(std::errc::invalid_argument));
                 }
@@ -707,16 +714,9 @@ protected:
 
         bool ok = true;
 
-        if constexpr (std::is_arithmetic_v<value_t> || std::ranges::output_range<value_t, char> ||
-                      std::ranges::range<value_t>) {
+        if constexpr (std::is_arithmetic_v<value_t> || mcc::traits::mcc_output_char_range<value_t> ||
+                      std::ranges::range<value_t> || mcc::traits::mcc_time_duration_c<value_t>) {
             return base_t::defaultDeserializeFunc(str, value);
-        } else if constexpr (mcc::traits::mcc_time_duration_c<value_t>) {
-            typename value_t::rep vd;
-
-            ok = base_t::defaultDeserializeFunc(str, vd);
-            if (ok) {
-                value = value_t{vd};
-            }
         } else if constexpr (std::same_as<value_t, mcc::MccAngle>) {  // assume here all angles are in degrees
             double vd;
             ok = base_t::defaultDeserializeFunc(str, vd);