The calculation of what is called the medical-loss ratio is crucial to insurance companies, because the law requires them to refund money to consumers if they spend too much on administrative costs.

But consumer advocacy groups and others see the insurers’ proposals and their lobbying for a more expansive definition of what would be permitted as an effort to water down the law by including too many administrative costs under the umbrella of patient care. “A lot of what they are hoping to shift over there does not  and should not  qualify to improve an individual policyholder’s quality of care,” said Wendell Potter, a former insurance executive who now is critical of the industry and represents consumers in the discussions with state regulators. On Tuesday, Senator John D. Rockefeller IV, Democrat of West Virginia, sent a letter to regulators expressing his concern that the insurers could have too much influence on how the regulations were being drafted. By his reckoning, insurers and their compatriots have submitted nearly 160 comment letters, totaling more than 600 pages, to the state regulators. Consumer advocates have submitted just 23, he wrote.

“The health insurance lobbyists failed to beat the health care reform bill in Congress  but with billions of dollars at stake, we cannot and we should not expect them to throw up a white flag and start looking out for the livelihoods of American families,” Senator Rockefeller said in a statement. “They’re working every angle of the implementation process to shirk their obligations under the new law.”

At stake, according to a report issued Thursday by Health Care for America Now, a coalition that supports the new law, is hundreds of millions of dollars when the law goes into effect next year. If the six largest for-profit insurers had had to meet the new standards last year, they would have been required to refund $1.9 billion, the coalition said.

The insurers contend that the advocates are discounting the value of an array of programs aimed at helping patients, which should be considered an aspect of quality improvement as part of the 80-cent minimum.