I cannot see realistic Gunnery

[schnorchel]

I use a steam version under Won7 64bits, I am pretty sure that I checked the realistic gunnery option in the realism page. I did several tries on intercepter the wellington bomber with 109e3 from her five or seven clock. but I found the there is totally no need to take a lead fire. if you use this way you will miss it. all you need to do is just put the cross hair on the target. That is very wierd.
BTW yesterday a try to switch the temerpature effect on in the game. But to my suprised is that I need to quit the game and restart it to really enable it. My question is do the game can really recognize my setting? did someone experience same thing as me?