When the head of the agency responsible for the troubled Healthcare.gov went before Congress for the first time since its foibles became apparent Oct. 1, she probably didn't expect that many questions would be on something else altogether.

But the website turned out not to be the focus of questions for Marilyn Tavenner by Republicans at the Ways and Means Committee hearing Tuesday. They were more interested in asking about cancellation notices being received by people who purchase their own insurance.

Unlike the computer contractors who testified last week before a separate House committee, Tavenner, who leads the Centers for Medicare and Medicaid Services, offered a formal apology for the website's dismal performance.

"We know that consumers are eager to purchase this coverage," Tavenner told the committee. "And to the millions of Americans who've attempted to use HealthCare.gov to shop and enroll in health care coverage, I want to apologize to you that the website has not worked as well as it should."

But most of the hearing was consumed with Republicans repeating a vow President Obama made often during the debate over the health law and ever since.

"If you like your health care plan you can keep your health care plan, period," said Rep. Peter Roskam, R-Ill., quoting the president. "No one will be able to take it away, no matter what."

That's turning out not to be the case. It's not yet clear exactly how many people will lose coverage, but likely millions of people who buy their own insurance are now getting letters saying their insurance plans are ending because they don't meet the requirements of the new law.

Many members of the committee, including Roskam, read letters from constituents who say they'll have to pay more for new coverage. "Can you understand the level of frustration and concern about what many Americans perceive to be a false claim from the administration?" he asked.

Tavenner said it's not that simple, and it's not all bad. Many people who say they like their current plans don't realize how little they cover.

"Sometimes they were in plans that they thought were fine until they actually needed hospitalization," she said. "Then they found out it didn't cover hospitalization, or it didn't cover cancer."

Now, she told the committee, health plans will have to meet the new minimum requirements of the health law.

"You can't be denied, you won't be kicked off a policy because you develop a problem," she said. "You may be eligible for tax credits depending on your income. So these are important protections that are now available through the Affordable Care Act. And I think that's important."

At the White House, spokesman Jay Carney pointed out that not everyone will pay more by changing plans. For some people, he said, "You're actually going to pay less for better coverage than what you're paying now."

How many will pay less is not yet clear.

Back at the hearing, Republicans also pressed Tavenner on when the administration will release figures on how many people have managed to successfully enroll in health plans so far.

To each question she gave the same answer: "That number will not be available until mid-November."

That number is important, because it's a key measure of the success or failure of the entire enterprise. Altogether the administration is counting on 7 million people to enroll between now and the end of March. But it's not just the number that will determine the viability of the insurance plans, but who signs up, as committee Chairman Dave Camp (R-Mich.) pointed out.

"I think critically important of that 7 million, 2.3 million of those need to be young and healthy," he said.

That's so there are enough healthy people in the insurance market to balance out those with pre-existing health conditions, who insurers will be required to cover.

Tavenner said she wasn't concerned about a slow start, even with the computer problems.

"The Massachusetts experience was very slow initially, and then it started to ramp up over time. We expect the same type of projections." She said.

Massachusetts implemented the same sort of requirement for most people to have insurance or pay a fine back in 2006.

Tavenner repeated the administration's promise to have the website's problems cured by the end of November. Tomorrow it's Health and Human Services Secretary Kathleen Sebelius's turn to testify before Congress.

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