The full amount of funds in the Available Balance will be utilized as margin on your position. When the Initial Margin is less than the Maintenance Margin, any Available Balance will be used to add margin to your position. Liquidation will be initiated when Maintenance Margin cannot be supported even after additional Available Balance has been used.
Under this mode, Initial Margin will be utilized for the current position only. It's the holder but not the engine who must add the margin.
Leverage Under Various Modes
Cross Margin is set as the default. In the modes of Isolated and Cross Margin, leverage can be adjusted but when an order is placed, the mode cannot be switched from one to the other, and the leverage cannot be changed either.