A loan will not fall into the service category. A loan would only fall into the small business/small farm or Community Development categories. Services are just that - services you provide like serving on the board of a group that benefits low/mod people. You might provide a loan to such a group as well and, if that loan meets the CD qualifications, get loan AND service credit.
Review the FAQs. There are extensive examples.
http://www.ffiec.gov/cra/qnadoc.htm