As is now routine for the last Friday of each month, the Centers for Medicare & Medicaid Services issued a slate of new rulemaking July 25. Among the agency's proposals: a change in the way Medicare calculates interest on overpayments and underpayments that would generally reduce the amount of interest assessed. Under the proposal, CMS would no longer count periods of less than 30 days as full 30-day periods for the purposes of assessing interest. The agency says the change will align its practices "to a commercial business model." In other rules and notices published in the July 25 Federal Register, CMS: To see the rulemaking and notices, go to http://www.access.gpo.gov/su_docs/fedreg/a030725c.html.