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A newly discovered glitch in the main ObamaCare website reportedly is giving thousands of people the wrong information about whether they qualify for premium subsidies.

The Philadelphia Inquirer discovered the glitch while entering hypothetical incomes into the calculator on HealthCare.gov. The newspaper found that the calculator is using the wrong year's poverty guidelines -- a simple mistake that, for months, has resulted in would-be enrollees getting inaccurate guidance.

Because of the glitch, some people may be initially told they qualify for subsidies when they don't. Others may be told they don't qualify when they do.

It's unclear how many people have been affected, but the mistake raises the possibility that thousands are giving up the hunt for insurance after being told, inaccurately, that they don't qualify for government aid.

"It's just another one of those, 'Why did they do that?'" Robert Laszewski, president of Health Policy and Strategy Associates, told the Inquirer.

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HealthCare.gov, and some of the state-run sites, were marred by technical problems after they launched last October. Many of those problems have been addressed, but the Inquirer report shows that glitches are still being rooted out.

The Centers for Medicare & Medicaid Services is fixing the newly discovered problem with the income calculator. A spokesman told FoxNews.com there is a "small difference" but "we have updated this tool for clarity."

The incorrect information has only been generated since about mid-February. CMS stresses that the estimates in question are unofficial, and customers are told that on the website itself.

"The window shopping tool on the learn side of HealthCare.gov is intended only to be used as an unofficial estimate that consumers can use before completing their application, which is where they get their official determination," spokesman Aaron Albright said. "We encourage consumers to complete their Marketplace application, where they will get an accurate determination of their tax credits."

The calculator in question is a tool meant to help those window-shopping for policies. It gives customers an initial estimate of whether they would qualify for subsidies.

Most federal programs are using 2014 poverty levels as the basis for these kinds of estimates, but the Affordable Care Act mandated that the 2013 guidelines be used this year (in part because sign-ups began last year).

Yet, HealthCare.gov continued to use the higher 2014 guidelines.

The result is that people whose incomes are just over the high end of the 2013 guidelines are told they qualify, only to find out later they don't.

Likewise, those just over the low end are told they don't qualify -- according to the Inquirer, only if they ignore that message, and click through to use another tool on the site, will they find out they do qualify.

The Inquirer reports this mostly would affect people in states that have not expanded Medicaid.

While the administration apparently is addressing the problem, its discovery comes a mere 10 days before the enrollment deadline. The White House and other branches of the administration are in a full court press to get people signed up -- and inaccurate estimates telling people they don't qualify for subsidies is another setback.

The insurance industry is waiting to see whether the administration enrolls enough young, healthy people to help offset the cost of taking on older, sicker patients.

Meanwhile, the American Medical Association, which originally supported the Affordable Care Act, is raising concern about another obscure aspect of the law which they claim could stick doctors with the tab for patients who skip out on paying their premiums.

The American Medical Association warned the rule could pose a "significant financial risk" for doctors and hospitals, and on Wednesday blasted out guidelines to help members try and avoid those costs. At issue is a 90-day "grace period" which lets patients who are not paying their premiums keep coverage for 90 days before it can be canceled.

Under the rule, insurers are responsible for paying any claims during the first month of that period -- but not necessarily for any claims during the final 60 days.

"Managing risk is typically a role for insurers, but the grace period rule transfers two-thirds of that risk from the insurers to physicians and health care providers," AMA President Ardis Dee Hoven said in a statement.