The are other pros. Maybe someone else is facing similar issue - communication may lead to collaboration in this case. If you communicate (early!) about some issues, mgmt has time to account for extra risks or delays.
So yeah, communication will get you promoted earlier than focusing on your tasks and keeping everything to yourself. I just cannot agree with the 10% for work and 90% for the communication ratio, that seems like way too much overhead. I think I would rather swap those numbers. Because how are you going to do anything meaningful if you work less than an hour a day?