Being Hispanic and not being URM may not be an advantage. So if you’re white with Spanish ancestors, probably no advantage; if you’re mestizo with Mexican ancestors, there may be an advantage. Each college, where not prohibited by law (like California public colleges) are free to make its own determination as to what is URM and what role, if any, it will play in the admission’s process. One such definition is:
http://www.hopkinsmedicine.org/Medicine/diversity/urm_definition.html