diff --git a/src/include/units/quantity_cast.h b/src/include/units/quantity_cast.h
index 38f821a9..73702716 100644
--- a/src/include/units/quantity_cast.h
+++ b/src/include/units/quantity_cast.h
@@ -346,10 +346,10 @@ template<Kind ToK, Unit ToU, typename K, typename U, typename Rep>
  */
 template<typename CastSpec, typename PK, typename U, typename Rep>
 [[nodiscard]] constexpr QuantityPointKind auto quantity_point_kind_cast(const quantity_point_kind<PK, U, Rep>& qpk)
-  requires (is_specialization_of<CastSpec, quantity_point_kind> &&
-              requires { quantity_kind_cast<typename CastSpec::quantity_kind_type>(qpk.relative()); }) ||
-           (PointKind<CastSpec> && UnitOf<U, typename CastSpec::dimension>) ||
-           requires { quantity_kind_cast<CastSpec>(qpk.relative()); }
+  requires requires { requires is_specialization_of<CastSpec, quantity_point_kind>;
+              requires requires { quantity_kind_cast<typename CastSpec::quantity_kind_type>(qpk.relative()); }; } ||
+           requires { requires PointKind<CastSpec> && UnitOf<U, typename CastSpec::dimension>; } ||
+           requires { requires requires { quantity_kind_cast<CastSpec>(qpk.relative()); }; }
 {
   if constexpr (is_specialization_of<CastSpec, quantity_point_kind>)
     return CastSpec(quantity_kind_cast<typename CastSpec::quantity_kind_type>(qpk.relative()));
diff --git a/src/include/units/quantity_point_kind.h b/src/include/units/quantity_point_kind.h
index 0503bba1..62142205 100644
--- a/src/include/units/quantity_point_kind.h
+++ b/src/include/units/quantity_point_kind.h
@@ -141,27 +141,27 @@ public:
 
   template<QuantityKind QK>
   [[nodiscard]] friend constexpr QuantityPointKind auto operator+(const quantity_point_kind& lhs, const QK& rhs)
-    requires requires { lhs.relative() + rhs; }
+    requires requires(quantity_kind_type qk) { qk + rhs; }
   {
     return units::quantity_point_kind(lhs.relative() + rhs);
   }
 
   template<QuantityKind QK>
   [[nodiscard]] friend constexpr QuantityPointKind auto operator+(const QK& lhs, const quantity_point_kind& rhs)
-    requires requires { lhs + rhs.relative(); }
+    requires requires(quantity_kind_type qk) { lhs + qk; }
   {
     return units::quantity_point_kind(lhs + rhs.relative());
   }
 
   template<QuantityKind QK>
   [[nodiscard]] friend constexpr QuantityPointKind auto operator-(const quantity_point_kind& lhs, const QK& rhs)
-    requires requires { lhs.relative() - rhs; }
+    requires requires(quantity_kind_type qk) { qk - rhs; }
   {
     return units::quantity_point_kind(lhs.relative() - rhs);
   }
 
   [[nodiscard]] friend constexpr QuantityKind auto operator-(const quantity_point_kind& lhs, const quantity_point_kind& rhs)
-    requires requires { lhs.relative() - rhs.relative(); }
+    requires requires(quantity_kind_type qk) { qk - qk; }
   {
     return lhs.relative() - rhs.relative();
   }