What do you mean by Total HP?
If it's going to check every turn, then it's going to keep rising... and rising... maybe I should put a GP on it...
If you have a Armagio and Sapphire Charger on your side, N = 25 + 5 = 30
If your Armagio got hit and his HP reduced to 10, N = 10+5 =15
The HP of Graviton will be updated at the end of every turn. But it will not keep rising.
If you have 2 Elite Armagio, N = 30 + 30 = 60 > 50, then Graviton will automatically become a Chimera