The US government just upended the economics of higher education—and may have effectively limited the extra help some professors offer to students too.

The Obama administration last week published rules to clarify who is eligible for employer health insurance under the Affordable Care Act—from seasonal workers to transportation crews on layovers to adjunct professors, the freelancers and part-time instructors that account for as much as three-quarters of all university instructors. The rules help determine whether their jobs will reach the 30 hours a week necessary to qualify for US employer-paid health insurance.

The guidelines established by the US government will make it easier for college administrators to calculate adjunct hours, but tougher for professors who spend extra time to tutor or help their students.

As universities struggle to keep pace with demand for degrees and keep costs in check, they have relied on adjuncts to teach all manner of classes, from anthropology to economics. At community colleges across Virginia, for example, adjuncts account for three-quarters of the faculty—and their numbers are growing three times as fast as full-time faculty over the last 15 years.

In the last year or so, many colleges and universities have limited adjunct hours—specifically to avoid having to give them health insurance coverage. The Obama rules further force a decision on just how dependent higher education remains on adjunct. “So if I am in the middle of a lecture, exam or finals, and my adjunct clock strikes 29 hours, do I pick up all the exams, stop lecturing mid-sentence and tell students, ‘sorry, I’m over the hourly limit imposed by the government and this institution, so if you completed the exam fine, if not too bad, take it up with the IRS, Obama and the ACA?'” one person wrote on the Chronicle of Higher Education’s website.

Unlike full professors who earn a salary plus benefit, adjuncts are paid by the class, based on the number of hours for the courses they are assigned. Pay varies widely from state to state and university to university, as little as a few hundred dollars per class to more than $10,000. Many educators barely eke out a living, despite their PhD’s and other credentials. “Those are poverty wages,” Kip Lornell, a George Washington University professor of ethnomusicology, told NBC News of his $23,000 a year pay. (That compares to a median US pay of $68,970.)

A growing number of adjuncts have turned to unions to improve their lot and raise their pay. Some hope they can earn enough so they no longer must teach at multiple universities to pay all their bills.

Even adjuncts who love to teach see the irony and the complexity in their stitched together careers. Writes adjunct Emily Van Duyne in a moving essay called “Why Buy the Cow?An Open Letter to Full-Time Faculty”:

As an instructor at three separate colleges, I maintain three separate emails, which I have to check at least twice a day, even on the weekends. I won’t go into the amount of hours I spend grading essays…. They are graded after my son falls asleep; they are graded before he wakes up; they are graded while I eat lunch; they are graded, in bits and pieces, while my students do a freewrite; they are graded in the single adjunct lounge with its single, barely working, computer, at a community college whose adjunct coordinator freely admits that the ratio of adjunct to full-time faculty is 5:1, a lounge that has contained, since I began working there almost two years ago, a sign that reads, “Adjuncts—please be sparing with your use of supplies. They must serve everyone. Thank you.

After hearing various proposals and formulas for time spent outside the classroom, the US government decided to provide “ease of administration,” with a guideline that an adjunct professor ought to earn 2.25 hours of service for each hour of teaching time. The Federal Register‘s math: For every hour in the classroom, the university counts 1.25 hours for tasks such as grading papers and preparing notes. Hours in faculty meetings or required offices hours are extra.

The number of hours outside the classroom clearly varies depending on the class, the instructor and homework assigned and such things as whether the person cares enough to respond to student emails and requests.

Counting the hours of part-time instructors was a time-consuming task for college officials and faculty for the last year and a half. Many universities are paring back their adjunct hours below that threshold so they are not responsible for health insurance premiums starting in 2015.

Adjuncts, who along with non-tenured faculty account for around 70% of the teaching force in US higher education, often do not have offices on campus for office hours or to prepare lessons. Yet they show up next to full-time professors in course catalogs and student rating sites.

“How about the endless hours of advising? Hell, I’m still advising and writing letters for students I had two and three years ago. It’s hard to say ‘no,’ but there’s no way to be compensated,” wrote one adjunct in response to the news reported by Inside Higher Ed.

The question of how many hours an adjunct works outside the classroom was left open to interpretation by universities, as long as it is reasonable. “Employers may credit more hours of service than would result” under the guidelines, the US government said—just as a college student could ask extra questions or turn in extra credit assignments.

The question remains whether the instructor has time to review them—as she’s juggling multiple adjunct gigs, a side job, or a combination of them all.