Republicans and Democrats on the House Oversight and Government Reform Committee are demanding more information about the profit margins of the company that produces EpiPens, after the company appeared to downplay those profits at a hearing last month.

Chairman Jason Chaffetz, R-Utah, and ranking member Elijah Cummings, D-Md., said in their letter to Mylan CEO Heather Bresch that when Bresch testified before Congress about profits from the device, she didn’t disclose that she was talking about profits realized after factoring in a 37.5 percent tax rate. That means her company makes even more money from EpiPens than many lawmakers realized.