diff --git a/index.bs b/index.bs
index ea77e7bc..74066c50 100644
--- a/index.bs
+++ b/index.bs
@@ -2008,7 +2008,8 @@ The base profile complies with that of <a href="https://aomediacodec.github.io/i
 This section specifies the conformance points of the base-enhanced profile.
 
 When the [=primary_profile=] field is set to 2, the following constraints apply to the [=IA Sequence=]:
-- There SHALL be at least one [=Mix Presentation OBU=] for at most 28 [=Audio Element=]s that parsers, which comply with the base-enhanced profile, recognize.
+- There SHALL be at least one [=Mix Presentation OBU=] for at most 28 [=Audio Element=]s that parsers complying with the base-enhanced profile recognize.
+- If [=additional_profile=] is set to less than or equal to 2, there SHALL be at most 28 channels in total across all [=Audio Element=]s in the [=IA Sequence=] that parsers complying with the base-enhanced profile can recognize. Otherwise, there MAY be more than 28 channels or 28 [=Audio Element=]s in the [=IA Sequence=].
 
 Capabilities of the IA parser, decoder, and processor:
 - They SHALL be able to support the capabilities of the [[#profiles-base|Base Profile]].