How it differs from standard search
The service hint says multilevel search matches query words across any columns. A matching word may appear in a different context from the one you expected. This mode should therefore not be treated as a guaranteed accuracy upgrade over standard search.
Why irrelevant records appear
For example, a query word may match text in another field while the other details of the intended subject do not match. That row is not relevant merely because it contains the word. Compare the combination of details rather than merging records based on one match.
When to use this mode
The menu recommends this mode for experienced users and specific queries. If you are new and have a phone, email or another clear identifier, first read the standard-search example. Choose multilevel mode for a defined task rather than by default.
How to review the response
Identify the field containing the matching word, then compare the other known details, source and time context where available. Keep unverified associations as hypotheses. When information is insufficient, uncertainty is an appropriate conclusion.