We have tried to recreate similar situation with 03.21.03 firmware version.
What we have done:
1. Features tab -> enabled ManDown scenario, set the position to Horizontal, Angle(deg):60, Timeout(s): 3, Send SMS To: *number*.
2. Keyboard tab -> Alarm Button -> set 1 click to "Man-Down On", 2 clicks to "Man-Down Off".
What did we achieve:
1. We get an SMS notification when the device changes it's angle by 60 degrees, SMS content: "ManDown val: 1".
2. We get an SMS notification when the device changes it's angle back to normal position, SMS content: "ManDown val: 0".
3. After clicking the Alarm Button 2 times, we were able to change the device angle without any SMS notifications.
4. After clicking the Alarm Button 1 time, Man-Down mode was enabled again and we started receiving SMS notifications again.
Hope this fulfills your desires as requested. Also, upvote the answer if it provided a solution to your request.