List the service location.. Google "prefers" that the listed address be one that customers can actually go to..
For the address, as much as I hate to say it, a microformat hcard solution might, I stress "MIGHT" help by using the adr tag and specifying what each address is for..
http://microformats.org/wiki/hcard
for example:
Code:
<div class="adr">
<span class="type">Service Center</span>:
<div class="street-address">169 University Avenue</div>
<span class="locality">Palo Alto</span>,
<abbr class="region" title="California">CA</abbr>
<span class="postal-code">94301</span>
<div class="country-name">USA</div>
</div>
<div class="adr">
<span class="type">Mailing</span>:
<div class="street-address">999 College Drive</div>
<span class="locality">Palo Alto</span>,
<abbr class="region" title="California">CA</abbr>
<span class="postal-code">94301</span>
<div class="country-name">USA</div>
</div>
This will give you both addresses and they are flagged appropriately and then let Google worry about it..