Not Sure. We were only there on a Friday afternoon.
The best way to get your answer is to email the abbey directly (go to their website, click on contacts/information and use the "informations visiteurs" email -- sorry, TripAdvisor doesn't allow links in these postings). I had a bunch of questions and they replied right away. You can write in English or French. You'll want to ask not only about the schedule, but also which services are open to the public
Get quick answers from Saint Benedict Abbey staff and past visitors.