I started this post as a request for help troubleshooting an issue with my new Mission SP1-L6H not switching between EXP1 and EXP2 on my HX Stomp. I had factory reset everything and followed the L6 manual and Mission's instructions exactly, and was convinced that something was broken. But about halfway through writing this post I stood up and pressed hard on the Mission pedal footswitch, and it switched from EXP 1 to EXP 2 just like in the videos. I think the issue is that the toe switch makes a nice clicky sound when you press it lightly, so I thought I was activating it. Turns out you have to really put some weight on it to activate it (which makes sense since you wouldn't want to accidentally trigger).
Anyway, I didn't come across this tip in my searching so I thought I'd go ahead and leave this here for future generations. TLDR: don't skip leg day.