Hi Marc, the answer on generic data-less Qs like this is always... it depends.
1st of all depending on the industry, categories, names and phone numbers they may not be allowed 2 listings, regardless if there are suite#s are not.
2nd I don't advocate adding suite#s if they don't exist. To me under the pure letter of the law, that equates to: Don't create a listing at a location where the business does not exist. If there is no suite, then... I think G is smart enough to figure it out.
But again that's me being cautious and by the book. I have in rare cases heard users say support told them to add a suite # but I don't think that was a seasoned phone rep that new the rules. And again it would not even help if those 1st considerations I mentioned did not warrant 2 listings.