diff --git a/docs/users_guide/framework_basics/dimensionless_quantities.md b/docs/users_guide/framework_basics/dimensionless_quantities.md
index 9547aec1..8b4f72e5 100644
--- a/docs/users_guide/framework_basics/dimensionless_quantities.md
+++ b/docs/users_guide/framework_basics/dimensionless_quantities.md
@@ -166,10 +166,11 @@ inline constexpr auto ppm = parts_per_million;
 
 ### Superpowers of the unit `one`
 
-Quantities of the unit `one` are the only ones that are implicitly convertible from a raw value
-and explicitly convertible to it. This property also expands to usual arithmetic operators.
+Quantities of the unit `one` are the only ones that are:
 
-Thanks to the above, we can type:
+- implicitly constructible from the raw value,
+- explicitly convertible to a raw value,
+- comparable to a raw value.
 
 ```cpp
 quantity<one> inc(quantity<one> q) { return q + 1; }
@@ -179,6 +180,14 @@ if (auto q = inc(42); q != 0)
   legacy(static_cast<int>(q));
 ```
 
+This property also expands to usual arithmetic operators.
+
+!!! note
+
+    Those rules do not apply to all the dimensionless quantities. It would be unsafe and misleading
+    to allow such operations on units with a magnitude different than `1` (e.g., `percent` or
+    `radian`).
+
 
 ## Angular quantities