MODULATION OF POSITION SIZE WITHIN A FOREX SYMBOL
The key is the ability to "modulate" a position size. If, in a "net position" system, there is the ability to sell or buy amounts less than the total net position, then we can add or subtract from an ongoing position. Although this exists in some brokers, with the typical MetaTrader 4 broker, the only way to accomplish position modulation is through individual "sub-positions" within an overall aggregate position in a symbol.
Within a symbol, considering the total position commitment, if we execute a new trade in that symbol which is "equal and opposite" then essentially we have no position or are "flat". I don't use hedging to do that. There's no need to maintain "opposite side" positions in the same symbol, in my view.
So I always decide to be either "long" or "short" and then I add or remove sub-positions to modulate that position size. And generally this results in my closing out the "last" position I may have added, thus my style of trading is often LIFO (Last In, First Out) and I would not typically want to use a FIFO (First In, First Out) approach EVEN THOUGH is may be equivalent in outcome; it's just not at all "natural".
If I can close out a "sub-position" with a profit; then I can re-enter that position on a retracement. Anyway... FIFO systems, especially those where there is no possibility to close out or add a "partial position" are deficient, and I won't trade on such a platform.
But "intra symbol" "hedging" which is what most Forex traders want to use, it not something I would use; since taking an equal and opposite position in the same symbol, is just equivalent to closing out that position.
[EDIT] The MetaTrader brokerages available to us outside the U.S. are not bound by FIFO or "net position" and so these are ideal for the style of trading I want to use.
[EDIT2] Those who are running "multiple strategies" in the SAME SYMBOL using Expert Advisors with "magic numbers" would need to have the freedom to execute opposite side trades in the same symbol. But I don't do that, and that "magic number" of Expert Advisor instance identifier is really quite confusing, and probably going out of style these days. Anyway, I decided not to do it. If I wanted to execute multiple strategies in the same symbol at the same time, I'd just create a distinct account to do that...