There's good news and bad news on Hillary Clinton's newly announced "Medicare for More" plan. While it could cover up to 13 million people, some of whom may already be covered elsewhere, it could also end up raising costs for some.

An analysis of the plan by consulting firm Avalere Health found that close to 13 million Americans age 50 and older who are currently uninsured, or who have individual coverage purchased through the private market, inside and outside the exchange, could be eligible for coverage under the Clinton plan.

However, coverage could end up costing more for some of those participants under the "unusual structure of the Medicare fee-for-service program," resulting not just in higher costs but also more benefit limits than insurance products available on the exchange.