AARP lobbying drops sharply after end-of-the-year spike

Certner said AARP was heavily involved in delaying for one year a 30 percent cut to physicians' Medicare payments, know as the Sustainable Growth Rate. That effort included advertising expenses that are counted in the lobbying disclosure.

Also, the seniors' lobby put out its voter guide for every federal House and Senate race, showing lawmakers' voting record.

Certner explained that many of those expenses are included in last quarter's numbers, including spending such as advertising that isn't usually considered lobbying. On the flip side, lobbying disclosures don't account for the work provided by the group's legions of volunteers.

"We take our entire lobbying shop dollars and include them in the report every quarter (and) our lobbying shop has dollars allocated to advocacy," Certner said. "What goes on the reports doesn't tell you the whole story. Sometimes it just depends on what part of the association is paying for it."