Apply suggestions from code review

Co-authored-by: sunghee-hwang <97494915+sunghee-hwang@users.noreply.github.com>

index.bs

@@ -253,7 +253,7 @@ IAMF is used to provide [=Immersive Audio=] content for presentation on a wide r
 Here are some typical IAMF use cases and examples of how to instantiate the model for the use cases.
 - UC1: One [=Audio Element=] (e.g., 3.1.2ch or First Order Ambisonics (FOA)) is delivered to a big-screen TV (in a home) or a mobile device through a unicast network. It is rendered to a loudspeaker layout (e.g. 3.1.2ch) or headphones with loudness normalization, and is played back on loudspeakers built into the big-screen TV or headphones connected to the mobile device, respectively.
 - UC2: Two [=Audio Element=]s (e.g., 5.1.2ch and Stereo) are delivered to a big-screen TV through a unicast network. Both are rendered to the same loudspeaker layout built into the big-screen TV and are mixed. After applying loudness normalization appropriate to the home environment, the [=Rendered Mix Presentation=] is played back on the loudspeakers.
-- UC3: Two [=Audio Element=]s (e.g., FOA and Stereo) are delivered to a Mobile device through a unicast network. Both are rendered to the same loudspeaker layout to be mixed. After mixing them, it is rendered to Binaural (or Stereo) with loudness normalization and is played back on the headset through the Mobile device.
+- UC3: Two [=Audio Element=]s (e.g., FOA and Non-diegetic Stereo) are delivered to a Mobile device through a unicast network. FOA is rendered to Binaural (or Stereo) and Non-diegetic is rendered to Stereo. After mixing them, it is processed with loudness normalization and is played back on the headset through the Mobile device.
 
 Example 1: UC1 with [=3D audio signal=] = 3.1.2ch.
 - Audio Substream: The left (L) and right (R) channels are coded as one audio stream, the left top front (Ltf) and right top front (Rtf) channels as one audio stream, the Center channel as one audio stream, and the low-frequency effects (LFE) channel as one audio stream.
@@ -268,10 +268,10 @@ Example 2: UC2 with two [=3D audio signal=]s = 5.1.2ch and Stereo.
 - Parameter Substream 1-2: Contains mixing parameter values which are applied to Audio Element 2 by considering the home environment.
 - Mix Presentation: Provides rendering algorithms for rendering Audio Elements 1 & 2 to popular loudspeaker layouts, mixing information based on Parameter Substreams 1-1 & 1-2, and loudness information of the [=Rendered Mix Presentation=].
 
-Example 3: UC3 with two [=3D audio signal=]s = first order Ambisonics (FOA) and Stereo.
+Example 3: UC3 with two [=3D audio signal=]s = first order Ambisonics (FOA) and Non-diegetic Stereo.
 - Audio Substream: The L and R channels are coded as one audio stream and each channel of the FOA signal as one audio stream.
 - Audio Element 1 (FOA): Consists of 4 Audio Substreams which are grouped into one [=ChannelGroup=].
-- Audio Element 2 (Stereo): Consists of 1 Audio Substream which is grouped into one [=ChannelGroup=].
+- Audio Element 2 (Non-diegetic Stereo): Consists of 1 Audio Substream which is grouped into one [=ChannelGroup=].
 - Parameter Substream 1-1: Contains mixing parameter values which are applied to Audio Element 1 by considering the mobile environment.
 - Parameter Substream 1-2: Contains mixing parameter values which are applied to Audio Element 2 by considering the mobile environment.
 - Mix Presentation: Provides rendering algorithms for rendering Audio Elements 1 & 2 to popular loudspeaker layouts and headphones, mixing information based on Parameter Substreams 1-1 & 1-2, and loudness information of the [=Rendered Mix Presentation=].