When searching for documents/assets you can add multiple search criteria separated by spaces. These multiple keywords are now treated in a logical OR fashion and thereby expanding the search result. This does not make sense because using Meridian Mobile a user will always be searching for that one particular document or asset.

The customer wants to see that either search is executed by default as a logical AND or at least the ability to switch between a logical AND option so that the selection is narrowed down which is what you want anyway .