Washington (CNN) -- The woman at the center of the Obamacare enrollment site, Centers for Medicare and Medicaid Services Administrator Marilyn Tavenner on Tuesday was the first government official to testify before Congress since the government's health insurance exchange went live on October 1. After nearly three hours of questions from both Republican and Democrats on the House Ways and Means Committee, here's what we learned:
1. Finally, an apology
After four very tumultuous weeks of open enrollment, Tavenner became the first government official to publicly apologize for the rocky rollout of HealthCare.gov.
"We know that consumers are eager to purchase this coverage and to the millions of Americans who have 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," Tavenner said during her opening remarks.
President Barack Obama has admitted his frustration and Health Secretary Kathleen Sebelius has expressed regret, but on Tuesday, Tavenner accepted responsibility for the site's failures.
"Obviously, I'm accountable for this," she said later in the hearing.
But Tavenner was insistent that the site is not beyond repair.
"I want to ensure you that HealthCare.gov can and will be fixed and we are working around the clock to deliver the shopping experience that you deserve," she said. "We are seeing improvements each week, and as we said publicly, by the end of November, the experience on the site will be smooth for the vast majority of users."
Despite Tavenner's claims of responsibility for the program's failures, none of the members of the committee signaled that she should be reprimanded. On the other hand, more than 30 House Republicans and at least two prominent Republican members of the Senate have called for Sebelius' resignation.
2. Insurance plans are being canceled
No fewer than 10 Republicans on the Ways and Means Committee held up or cited letters sent to constituents saying that their health insurance plans were going away. Most of these legislators quickly followed up with references to a talking point at the center of Obama's pitch to consumers both before and after the Affordable Care Act was passed.
"If you like your health care plan, you can keep your health care plan," the president repeated in speeches, weekly addresses and even the 2010 State of the Union address.
At Tuesday's hearing, Republicans called that promise misleading.
Tavenner acknowledged that while some insurance companies had decided to stop offering certain plans on the individual market, the ACA did not force them to make that decision, and consumers whose plans have been canceled now have more comprehensive plans available to them.
"If, in fact, the issuer has decided to change the plan -- it didn't have to," Tavenner said. "Plans were grandfathered in in 2010 if they didn't make significant changes in cost-sharing and this sort of thing, they could keep the plans that they had."
Companies that decide to create new plans, Tavenner continued, must conform to new mandates under the ACA. These include a ban on rejections due to preexisting medical conditions, and new mandated benefits such as hospitalization, emergency services and maternity care. In response to repeated Republican questioning, Tavenner recommended that consumers who lose their coverage explore the options available to them on the new federal exchange.
"They can call the call center today and we will help them," Tavenner said. "They can go online and if they're not successful we can help them through the call center. We also have people in their individual markets that can help them in person. So there are more methods than just the website. And I think that's important."
3. Initial enrollment will be low
Since the ACA passed in 2010, Obama administration officials have pointed to the initial months of Massachusetts' health reform implementation as a predictor of how the nation-wide rollout might go. While repeatedly emphasizing that her agency wouldn't be releasing any enrollment information until mid-November, Tavenner used this example again on Tuesday as one reason why the first round of numbers might be lower than expected.
"We expect the initial number to be small," Tavenner said. "And I think you've seen that in our projections, and that was the Massachusetts experience as well."
Later Tavenner expanded on that explanation saying, "The Massachusetts experience was very slow initially and then it started to ramp up over time. We expect the same type of projections."
In recent days, White House officials have cited a study in the New England Journal of Medicine that found the vast majority of the consumers who enrolled in the first month of the Massachusetts health insurance exchanges were Medicaid eligible.
The study found that just 123 premium-paying enrollees signed up in Massachusetts during the first month, compared with 10,000 people who signed up for Medicaid or plans with no premiums.
4. The partisan gulf remains wide -- and Democrats are standing by Obamacare
As Republican after Republican read testimonials from their constituents about the disastrous effects the Affordable Care Act is having on insurance policies, and the tortured experiences many have had trying to enroll online, the stories coming from Democrats were quite different.
Supporters of the law acknowledged that the first month of open enrollment had been less than pleasant, but the stories they recounted had happy endings.
California Democrat Rep. Xavier Becerra told the story of Andrew Striker, who waited three hours to purchase insurance online, but was happy with his insurance in the end.
"The good news for Mr. Striker is he's saving $6,000 as a result of being able to apply for the plan," Becerra said. "So it's unacceptable for anyone to have to wait even three hours, and even though he says that he would have waited all day given the result he got, what we want is for everyone to experience the $6,000 savings -- maybe not that much, maybe more."
Rep. Danny Davis, a Democrat from Illinois, used his time to list off statistics demonstrating the successes of open-enrollment in his state.
The most passionate defense of the health care law came from New Jersey Democratic Rep. Bill Pascrell, who chastised Republicans for trying to kill the law rather than working to improve it, as Democrats had done when faced with health reform they opposed, President George W. Bush's Medicare Part D.
"We lost the policy fight, and what did we do? We went back to our districts and we told our seniors although we voted no, we personally believe -- and will work with the Bush administration to make it work, that's what we did," Pascrell said, standing from his chair to face his colleagues. "And how many of you stood up to do that? None. Zero. Zero."
5. Capacity is improving
In a statement that galled many Republicans on the committee, Tavenner said that despite all of its hiccups and inconsistencies, HealthCare.gov is currently functioning.
"The system is working," she said. "We'd like for it to work better and that's what we've committed to do by the end of November."
For weeks, administration officials have said that performance is improving every day, and on a conference call with reporters on Tuesday afternoon CMS officials gave an update on consumers' ability to create an account on HealthCare.gov, a major bottleneck in the site's early days.
"Now we are able to process nearly 17,000 registrants per hour, or five per second, with almost no error rates," CMS communications director Julie Bataille said on the call. "So that's the number of individuals who are completing that full account creation process, that first step in the application."