None of this stops you losing money. These limits control how much you can lose in a bad stretch. They do not make a bad stretch less likely, and nothing here can. If anyone tells you automated trading takes the risk out, they are lying to you.
A limit is not a promise about price. Stopping at 8% means the engine stops trying at 8%. It does not mean you get out at 8%. If the price jumps overnight while you are asleep, or the exchange stops filling orders for a while, you get whatever price exists when your order actually fills. That is true on every venue, ours included.