Inside <mixchange> the different changes of the breathing gases are given for <descent>, and <ascent> respectively.
<profile>
<inputprofile>, <profile>
(see also <profile>, and <inputprofile>)
<!-- (change of breathing gas during) descent -->
<inputprofile>
<waypoint>
<depth>0.0</depth>
<divetime>0.0</divetime>
<switchmix ref="air"/>
</waypoint>
<waypoint>
<depth>35.0</depth>
<divetime>210.0</divetime>
<switchmix ref="Trimix1"/>
</waypoint>
<waypoint>
<depth>50.0</depth>
<divetime>300.0</divetime>
<switchmix ref="Trimix2"/>
</waypoint>
<waypoint>
<depth>80.0</depth>
<divetime>480.0</divetime>
<switchmix ref="Heliox"/>
</waypoint>
<waypoint>
<!-- remaining time at bottom shall be 10 minutes, then ascent begins -->
<depth>80.0</depth>
<divetime>1080.0</divetime>
</waypoint>
</inputprofile>
<!-- change of breathing gas during following ascent -->
<!-- (for the ascent profile is to be calculated, there don't appear any -->
<!-- "divetime" attributes inside the <waypoint> statements) -->
<mixchange>
<ascent>
<waypoint>
<depth>80.0</depth>
<switchmix ref="Trimix2"/>
</waypoint>
<waypoint>
<depth>50.0</depth>
<switchmix ref="Trimix1"/>
</waypoint>
<waypoint>
<depth>35.0</depth>
<switchmix ref="Nitrox4060"/>
<depth switchmix="Nitrox4060">35.0</depth>
</waypoint>
<waypoint>
<depth>15.0</depth>
<switchmix ref="Nitrox2080"/>
</waypoint>
<waypoint>
<depth>5.0</depth>
<switchmix ref="oxygen"/>
</waypoint>
</ascent>
</mixchange>