Per the help file for Specifying Multiple Search Criteria "You can add the same attribute to the search criteria twice and enter different values. The search will return objects meeting either value (an OR search) regardless of whether With all of these criteria or With any of these criteria is selected in the Find section."
That means that if you have a multi-valued attribute, you cannot currently create an AND search criteria to find objects which have two or more specified values. For example, you may have a mult-valued attribute named CLASSIFICATION, and want to find objects which have CLASSIFICATION values of both "Turn Signal" AND "LED". You can't create this search today, (but you may think you can if you have With all of these criteria selected in the Find section and are not aware of the limitation noted in the help file). As a result, your search will return all objects which have a value of "Turn Signal" OR "LED". So you will get objects which are Incandescent Turn Signals, LED Turn Signals, LED Marker Lights, LED Brake Lights, LED Dome Lights, etc., instead of just LED Turn Signals.