Earlier quoted context omitted.
That doesn't mean a student doesn't miss something when they're away from school. Self-paced just changes the timing. The dynamic is not comparable to a work environment where someone else might be able to do the work for you. No one can learn for your child when they are away, and that fact doesn't change with less rigidly structured Montessori schools.
it definetly does mean that they don't miss anything, because the students just resume where they left off without any pressure to speed up.
I'm not debating the merits of Montessori schools. I'm saying the "missing time" aspect of your comment does not have a good analog from work to learning. That's all.