Paid on bookings or invoicing?

I've recently learned that many of my peers (even those that sell services) are paid on bookings, not invoicing. 

My boss quit recently and walked away from 100k that he worked his ass off for because of our commission structure. We aren't paid until we invoice a project, which many times isn't invoiced until the project is complete. I'm curious if this is common for tech sales (specifically cybersecurity).