I think i just noticed something. There was a Level 41 (Brigadier General), Level 39 (Colonel), Level 34 (Lt. Colonel) ,Level 31/32 (Major), Level 29 (Captain), Level 25 (2nd Lieutenent) and a Level 22 (NCO rank) all present in the video.
What i think at the moment is this:
NCO Rank = Levels 20 - 22
2nd LT = Levels 23 - 25
1st LT = Levels 26 - 28
Captain = Levels 29 - 30
Major = Levels 31 - 33
LT Colonel = 34 -36
Colonel = Levels 37 -39
Brigadier General = Levels 40 - 42
Major General = Levels 43 - 45
LT General = Levels 46 - 48
General = Levels 49 - 50 ?
This is just a rough estimate through averaging out ranks, if its correct then the OP was correct about there being 50 ranks. So i think its plausible