The head of the Centers for Medicare and Medicaid Services said Tuesday that the expansion of cheaper, short-term plans wouldn’t lead to higher premiums on Obamacare exchanges.

CMS Administrator Seema Verma said the agency is assessing the impact that the expansion could have on Obamacare premiums. But she disagreed with warnings from numerous experts that the cheaper plans would cause prices on Obamacare’s insurance exchanges to surge.