Default [Q] Unable to Search Contacts by Last Name Only (Last Name = Numbers)

I do store tech support for a coffee company with over 150 stores. I have contacts synced to my exchange account with the first name Store and the last name their store number. With my old phone (Samsung Galaxy Nexus) I could do a search contacts and just enter the last name, such as 354 and it would bring up Store 354. With the LG G2, if I type in just 354 it will only bring up phone numbers that have 354 in it. Store 354 does not show up in the results. If I type in "Store 354" it shows up. Is the phone seeing "just numbers" in my search query and thinking it doesn't need to search names? Is there any setting I can change to fix this? Thanks.