What section of Regulation O are you looking at regarding “maintenance” of a loan – this will help me understand your question better? Without specifically knowing what you’re looking at I would look to how extension of credit is defined in 12 CFR 215.3. Specifically it says
[a]n extension of credit is a making or renewal of any loan, a granting of a line of credit, or an extending of credit in any manner whatsoever, and includes.. (5) An increase of an existing indebtedness…