Netting
The netting position accounting model allows you to have only one open position in an investment instrument. Conditions for any investment instrument using the netting model:
You can’t open two positions in different directions (short and long) of the same volume – they will close each other.
If the volume of your new long position is bigger than your existing short position (or vice versa), the existing position will reverse in the opposite direction.
If the volume of your new long position is smaller than your existing short position (or vice versa), the existing position volume will reduce by the opposite position volume.
Open orders in the same direction are summarized.
In any case, there will always be only one position in an investment instrument.
Hedging
The hedging account allows you to open as many positions in the same instrument in different directions as you want, in case there is enough margin for opening and maintaining them.
If you work with the hedging accounting model and already have an open position in some instrument and want to open a new one, you will just get another open position. Unlike the netting model, in the hedging model opening a new position has no influence on existing ones.