No, this is not for resetting the service indicator, it is several test functions that relate to the instrument cluster. I posted previously about accessing the temp function, but there's also a link to a list of all the possible functions.
http://www.z4-forum.com/forum/viewtopic.php?f=9&t=39385&p=549414#p549414
Clarification: If you press/hold the S/R button, THEN turn on ignition, it'll go through the test function, then on to the Reset function.
If you press/hold the S/R button AFTER turning on the ignition, you only get the test function, not the Reset function.