(CNN) When Republicans in the House of Representatives voted narrowly to repeal and replace Obamacare earlier this month , they weren't entirely sure of the bill's impact on the deficit or on the millions of Americans who gained coverage through the health reform law.

Three weeks later, they're about to find out.

The Congressional Budget Office, the non-partisan scoring agency, will announce its much-anticipated update on the American Health Care Act Wednesday afternoon. The analysis will finally provide crucial figures that the Senate needs to move forward with crafting its own plan.

The agency has already issued two reports on earlier versions of the GOP health care bill, but lawmakers continued to make changes up until the last minute to secure enough votes for passage.

Here's what to watch for in the updated score:

Total savings

The CBO score is high-stakes. Republican leaders are watching closely not only just to be able to say their bill saves money, but to make sure the CBO confirms it hits the $2 billion savings goal laid out by the budget committee. Here's the issue: In order to use a process known as reconciliation in the Senate, which allows a bill to be approved with just 51 votes, the AHCA has to save $2 billion over the next decade.

If it doesn't, that's a fatal flaw, which means the House would have to vote again on a new bill that hits that target or forfeit its right to use the reconciliation process.

Now, House and Senate Republican aides are confident their legislation will easily hit that goal. An earlier CBO score of the bill showed the legislation saved $150 billion over a decade. But there is an additional hiccup.

Republicans can't just save $2 billion overall. They have to save $1 billion in the Senate Finance Committee and then $1 billion in the Senate HELP Committee.

Some experts have also raised questions in Vox and Bloomberg as to whether last-minute changes to the bill that would allow states to waive certain regulatory requirements of Obamacare might make insurance leaner and cheaper. That could lead more consumers to buy policies, many of whom would be eligible for federal government tax credits available under the AHCA. That could end up costing the government more money than originally anticipated.

Also, Republicans have committed to putting more money in the State Stability Fund to help states and insurers deal with high-cost enrollees.

Coverage numbers

This is the biggie. Earlier scores of the American Health Care Act predicted 24 million fewer people would have health insurance in 2026. The Medicaid rolls would be 14 million lower than they would be under current law.

These numbers became a key talking point for Democrats railing against the GOP bill and even spooked moderate Republicans out of voting for the legislation they feared could haunt them in the midterms in 2018.

It's unclear how the CBO will score the latest version of the bill, which gives states more room to waive some Obamacare regulations like community rating, which barred insurers from charging people with pre-existing conditions more for policies, and essential health benefits, which required insurers to provide comprehensive coverage.

Conservatives argue that scaling back these requirements will allow insurers to offer a wider variety of policies and will lower rates, enticing more people to sign up for coverage. But consumer advocates say these changes could render insurance unaffordable for the millions of Americans with pre-existing conditions.

The CBO report will be able to give lawmakers their view on that.

Premium costs

Republicans in the House have claimed the changes they made in the latest version of the health care bill were all aimed at lowering premiums for consumers. It was a key refrain from the conservative House Freedom Caucus who had railed against the original version of the AHCA, but ultimately came on board with the revised option.

The original version of the AHCA would lower premiums for younger Americans, according to the CBO, but only because many older consumers would drop their health insurance because it got too expensive. The bill would allow insurers to charge those in the 50s and early 60s higher premiums compared to younger enrollees.

The more recent amendments, which would weaken Obamacare's protections for those with pre-existing conditions, are also expected to lower premiums for healthy consumers, but raise them for the sick.

CBO is expected to weigh in on how these changes will affect premiums.