To increase AE voltage to a specific voltage you need to do Nettodat coding using NCS dummies. Change the custom value to OC,2C and then code it in. This value seems to be rather on the safe side of 13.7 volts. Changing it to wert_09 I am not sure the voltage of that setting
As for your other question about seat occupancy refer to this thread
http://www.e90post.com/forums/showthread.php?t=583819