Well I've been messing with this for hours now. Starting to think it's some kind of bug. Even just displaying the values of the variables using messages doesn't work. I should be getting:
1000,0,5000,500
-1000,0,5000,500
0,500,5000,500
2000,0,5000,500
-2000,0,5000,500
0,-500,5000,500
3000,0,5000,500
etc
It's actually returning:
1000,0,5000,500
-1000,0,5000,500
0,0,5000,500
2000,0,5000,500
-2000,0,5000,500
0,0,5000,500
0,0,5000,500
and keeps returning the same 0,0,5000,0 over and over again.
If I set the repeat to more than 27 (the number in the in-sequence list) it will keep running well after the arguments should have been exhausted. Starting to think having multiple when-arguments running at the same time is getting confused somewhere.
I updated the link in the first message with the current version of the test mission.