I was reading "English Grammar in Use" and came across the next exercise:
Ben can’t meet us on Monday. (He / work) late.
The correct answer is "He is working late", but I cannot understand why. There is a grammar written in this book page before:
We use the present simple when we talk about timetables and programmes
You can use the present simple to talk about people if their plans are fixed like a timetable
What's wrong with the answer "He works late"? Why cannot we consider that Ben should work late on Monday due to his work schedule, and this is not his desire, but obligation?