hmm, can't get it to work with max assist either.

Am I missing something?
Well then, I guess either you struggle with how to time it (happens), or something is done incorrectly... Kinda hard to tell without seeing a video sadly.
Your Encounter tool seems to be correct though
The important parts are :
Using the timer audio cue helps a lot.
If it still doesn't work, it might actually be a bug, but I doubt it as this part was tested out extensively...
Take a look I made you a video.
https://s1.webmshare.com/KJGJq.webm
Double checked that the seed is for file1 btw