This setting is specific to Standard mode only. This feature will open a “hedge” or opposite direction when martingale hits certain level. The idea is for you to at least, take some profit in the midst of the drawdown you experience during the incorrect direction.

For example: you set HedgingLevel at 5.

It means, when bot opens 5th martingale position, it will also open the hedge. For example:

EURUSD BUY 0.01
EURUSD BUY 0.02
EURUSD BUY 0.03
EURUSD BUY 0.04
EURUSD BUY 0.05 – at this point, hedge opens
EURUSD SELL 0.01

The hedge will always start at the 1st lot size. As price keeps going the wrong way, more hedge positions will open until HedgingClosePercentage (please see this setting article for more details) is hit.

While hedge sounds like a great idea, the downside though, if position reverses, your hedge becomes a losing position. Say, in the example above, position reverses before hedge closes for profit, the EURUSD SELL 0.01 becomes a losing position that remains open. Imagine if you have 4 hedge positions open, and before they close for profit, price reverses. Your original martingale will be in positive, while your hedge will now all be in negative.

So tread and trade carefully.