Variable-hour workers are the top source of IRS penalty exposure — and most employers don't find out until a letter arrives.
ACA 360 specializes in tracking and managing variable-hour populations with the precision the IRS requires. We handle classification, measurement, eligibility tracking, and documentation — so you're not scrambling when a Letter 226-J shows up.
Under the ACA, a variable hour employee is someone whose hours you cannot reasonably predict at the time of hire. Their schedule, role, or assignment makes it impossible to classify them as full-time or part-time from day one.
This matters because it determines which measurement method you're legally allowed to use — and getting it wrong can expose you to retroactive penalties.
Each classification carries different ACA obligations under IRC Section 4980H. Misclassify one employee and the exposure compounds across your entire workforce.
| Classification | Definition |
|---|---|
| Full-Time | 30+ hours/week or 130+ hours/month |
| Part-Time | Consistently below 30 hours/week |
| Variable Hour | Hours cannot be reasonably predicted at hire |
| Seasonal | Hired for 6 months or less during a defined season |
Misclassifying a variable-hour employee at hire leads to a chain of compliance failures. All it takes is one employee receiving a premium tax credit for the IRS to issue a Letter 226-J. From there, penalties can reach tens of thousands per year.
Assuming low-hour employees are automatically exempt from ACA tracking obligations.
Relying on payroll software to monitor ACA eligibility — it reports hours, but it doesn't apply the look-back method.
Failing to offer coverage during the full stability period — even after the employee's hours drop.
Not documenting the measurement method start date, logic, and offer timing — leaving you exposed in an audit.
The look-back measurement method has three phases. We run all three, document everything, and produce reports your auditor, broker, and HR team can all read.
Hours tracked on a rolling monthly basis. We alert you when an employee is trending toward full-time status — giving you time to act before a coverage deadline passes.
Monthly reports showing exactly who's approaching eligibility — with summary views for HR, management, and your benefits broker.
We manage every phase — initial measurement, administrative, and stability — with every decision documented and defensible in an audit.
If you can't produce documentation showing your measurement method start date, calculation logic, and offer timing, you're vulnerable in an audit — even if your intent was correct.
The IRS holds every employer to the same standard, regardless of industry complexity or HR bandwidth.
Multi-location, high-turnover crews with tipped pay structures.
Per diem and PRN staff with hours that rarely follow a pattern.
Seasonal schedules that create gaps in eligibility tracking.
Swing shifts and demand-driven staffing with minimal HR infrastructure.
ACA 360 reconstructed our payroll and determined we were not actually an ALE. They submitted all the required paperwork to the IRS. Several months later, we received confirmation closing the 2021 tax year and releasing us from all ESRP penalties.
Without ACA 360, we would have paid thousands in penalties and possibly closed a new location, putting our employees out of work. ACA 360 saved our business.
Starting with the 2024 reporting year, federal law limits the IRS to a 6-year window for ACA penalty assessments. Good news going forward — but if your filings from 2023 or earlier had errors, you may still be at risk. ACA 360 can audit your history and address it before the window closes.
A 15-minute conversation tells you exactly where your variable-hour exposure stands — and what monthly tracking should look like for your workforce.