So, today I attacked a pirate fleet. Before I sent my ships out, I ran the simulator *many* times, correctly imputing tech levels before hand. No losses, easy win projection every time (since the results are not always the same, I ran the simulator like 20 times).

I send the fleet out, it's a draw, and I lose a destroyer. If the simulator is this unreliable, it may as well not be in the game - if it tells me I win with no losses 20 times and then I get a draw with a loss of a valuable ship, then it's useless.

You get better results with the simulate if you buy the officer : Coach 
So you can also account the reasaerch from the pirates !

But still the simulator can only give yoz an idea how the battle might end.

You can simulate the battle many times and you will see that results aren t always the same.

Thats normal because you don t know which units attack the other...

You also can manage your units in battle by yourself. So the simulator gives you just an idea !!!  He don t calculate every battle in detail because that s simply not possible. And to be honest i like a bit of a Surprise.

For pirates take more troops as needed !

          You should not trust the simulator. Simulators always gives different results. It is random. So you need to send more fleet to pirates. If simulator says 10 destroyers is okay for battle. You can send 15 destroyers. I have got officer Coach 3. - http://joxi.ru/EA4oLVMSovj5v2 For example, simulator gave me this false result ; http://joxi.net/vAWnzj0tgBax12 And, I forgot to send a little more fleet to pirate. As a result, I lost my space wanderer after the battle; http://joxi.net/krDMzwNHKgWopm
         Also if you will attack to xerj, you should send one fighter to pirate, firstly. Because there might be scourge. The only way to detect these invisible mines. You can send the fleet after you find out if scourge exists.