For the past three months, the LePage administration has been clear on two things: the size of the shortfall in the Department of Health and Human Services budget and its cause — overly generous eligibility standards for the state’s low income health care safety net.

Now, it can’t be sure of either. Tuesday, DHHS Commissioner Mary Mayhew announced that a computer glitch resulted in 19,000 ineligible people remaining on the MaineCare rolls, which means a still-unknown part of the shortfall is the result of mismanagement, not program design.

Mayhew’s announcement comes at a pivotal point. With only about a month left in the legislative session, lawmakers are trying to finish work on a correction of the budget’s second year, which begins July 1. The Legislature just finished work on a revision of the current year’s budget, with savings that included dropping 14,000 parents of MaineCare-eligible children from the program.

The computer glitch revelation could be good news because it lowers the amount of money that needs to be cut from next year’s budget. It could be bad news because the federal government will be looking to get back any money it paid in error. It matches the state’s contribution at a two-to-one rate.

Good news or bad, it raises questions about the administration’s competence to judge either the size or the cause of the DHHS problem. Mayhew revealed that her department knew about the computer problem in January while she was still advocating dropping 19,000 childless adults known as noncategoricals from the MaineCare program, projecting that it would save the state $20 million a year. At that time, the governor was critical of lawmakers who were probing into the department’s budget figures and questioning how the shortfall grew so large in such a short time, even though only a small percentage of the deficit could be attributed to new people coming into the system. Those questions now look very pertinent.

With only weeks to go, lawmakers will have to work hard to close the budget gap responsibly while the numbers they are working with keep changing.

And the administration will have to address a different deficit — a shortfall in credibility.