My heater cover is off center as well and I have never broken the WPA. What makes you think that you will?
If it really bugs you though, you can always pull the heater cover off and put it back on again and see if it straightens out. Either that, or very, very gently, put your finger in the top and slowly bend it towards center. Prior to this though, make sure that the heater cover is pushed all the way down till it's touching those three screws. Make sure though that your LSV has totally cooled off before trying this so you don't burn the fuck out of your fingers. There is a gamble though in doing this in that you could break the heater cover or lose a shim.