With this case law, the Court seems to revisit the argument of the “proportionately greater burden” on part-time employees. Indeed, reaching the threshold for overtime constitutes a proportionally greater burden for them than for full-time employees. The Court thus reverts to an earlier judgment, Helmig (1994), when it had still ruled that there is unfavourable treatment (of women compared to men, since women are more likely to work part-time) only to the extent that the “total remuneration“ paid to full-time employees is higher than the remuneration paid to part-time employees who work the same number of hours as a full-time employee - either by working overtime or additional hours. However, the ruling is not entirely unexpected. The Court itself had already partially adjusted its view in the Elsner-Lakeberg case (2004) by ruling that a part-time teacher was treated more unfavourably (and bore a greater burden) if - like full-time teachers - they were paid overtime only when those overtime hours exceeded three hours per calendar month. The threshold had to be prorated, according to the Court. However, in the Voss ruling (2007), the court seemed to have reconsidered that reasoning. It did refer again to the principle of "total remuneration" to rule that there is also unfavourable treatment when both part-time and full-time employees receive lower remuneration for hours "outside their normal duty roster". Indeed, part-time employees who - through overtime or additional hours - still worked a full-time duty roster would then receive lower “total compensation” than full-time employees who worked the same number of hours.
The ruling of 19 October 2023 (C-660/20) may also have implications for part-time employees in Belgium. This is because, while full-time employees in Belgium in principle receive overtime pay for all hours “above the working hour limits” (in principle above 9 hours per day and/or 40 hours per week), part-time employees in fixed employment schemes are still subject to a credit of 12 hours per calendar month above which overtime is due. Similarly, in variable employment schemes, overtime is only payable above a threshold equal to the number of weeks in the reference period multiplied by 3 hours and 14 minutes (with a maximum of 168 hours). This raises the question of whether this imposes a greater burden (and hence unfavourable treatment) on part-time employees.