Understanding Interactive Broker's Trail Limit Stop order

[mangojoe]

Good day,
I struggle to make sense of how to correctly fill out a trail limit order for selling a stock even if I have the manual next to me on Interactive Brokers. Especially with 2 fields being mutually exclusive.
I wrote these hints down for myself, correct me if I am wrong. My aim is to lock in a profit when there is a bigger drop.

trail amount = "distance" in which stop price follows market price up but not down
stop price = price that market needs to hit before order becomes active / a limit order
stop price = market price - trail amount
limit offset = used to calculate minimal price that stock is sold for
where minimal sell price at time of submitting order = market price - trail amount - limit offset

Now to keep it simple for me I stuck to: My stop price + My trail amount = Current market price
In this sample order with A2M @ 19 AUD at the moment the trail amount is smaller than the current gap between stop price and market price.



In what scenario would one use that? Or how does it act differently?

 

[mangojoe]

Here is an active order that is 2 days old but I also can't follow why it is what it is.
Here is how I submitted it with A2M @ 18.87 (I submitted outside of trading hours, if that matters)

How it looks now with A2M @ 19

I expected it to show a price of current price - trailing amount: 19 - 1 = 18
but it shows 17.67