Clarify optionality of refinement / AC-Review for minor changes to ac…

…tive charters

index.bs

@@ -1950,12 +1950,16 @@ Minor Changes to Active Charters</h4>
 	Substantive changes to a [=charter=] (including [[#charter-extension|extensions]])
 	that do not affect the way the group functions in any significant way
 	<em class=rfc2119>may</em> be approved by a [=Team Decision=],
-	in which case they do not require an [=Advisory Committee Review=].
+	in which case they do not require [=charter refinement=] nor [=Advisory Committee Review=].
 	The following are examples of such changes:
 	the addition of an in-scope deliverable,
 	a change of [=Team Contact=],
 	or a change of [=Chair=].
 
+	The [=Team=] <em class=rfc2119>may</em> nevertheless choose
+	initial [=charter refinement=] and/or [=Advisory Committee Review=]
+	when it thinks the changes would benefit from more scrutiny or explicit buy-in.
+
 	Though [=Advisory Committee Review=] is not required,
 	such changes <em class=rfc2119>must</em> still be announced
 	to the [=Advisory Committee=],