OMG The way OP writes is making my head spin. How can you have both long and short at the SAME TIME?? They will cancel each other out! Anyway, try my suggestion as written above to see if that remotely resembles what you're looking for.
You will be surprised how many retarded people there are thinking they gain some sort of edge by simultaneously opening a long and short position in the same underlying. In the past some brokers (mostly bucket type brokers) offers such feature but changed regulations now forbid such.
It’s generally against exchange rules and even SEC/finra regulations to post bids and offers concurrently. It can be construed as acting as a market maker (violate exchange rules) or painting the tape/churning (sec/finra). Trying to arbitrage this as a retail trader is a fools game. If you are good at the execution you will likely get filled with one way risk. If you are bad at it, you will incur lots of cancellation charges.
I tell you if you bring forth a convincing argument why a simultaneous long and short position in the same stock is not one single net position (if sizes are different) or a flat position (if sizes match).
At the risk of adding to the confusion, I think what OP wants to do (I've asked that question a while back) is to buy long but also short that position from time to time. For example, buy XYZ at 1 sell at 5. If at 4 the price looks to reverse, short "a new group of shares" with a buy at 3, while leaving the original long alone. Does that make sense? In any case, no it's not allowed. Unless of course you have brokerage accounts from 2 different brokers. In which case you can long in one and short on the other.
No, it does not make any sense. When price reaches 4 you sell whatever size you want to sell and that realizes pnl (unrealized moved to realized) and when you buy at 3 the avg price will be adjusted. (all under the assumption the sell size at the price of 4 does not exceed the original size). Whenever you get filled then if the size of the fill (buy=positive size, sell=negative size) moves closer to 0 then you realize pnl and if it moves further away from 0 your avg price gets updated. This is absolute basics and anyone who does not understand this should not be trading but learn this first. Re your latter comment, from a regulatory standpoint even that is not allowed when the position originates from one and the same entity.
Right but your reply only states the obvious, that your long/short gets adjusted as you proceed. But what OP is trying to do is make money from both long and short without getting out of the long. Again, that's just not possible, nor legal.
The net effect is 100% identical to simultaneous long and short positions. Which part of that is unclear to you?