True. But then even the limits are somewhat fuzzy. I find with an experienced or well led team, that if you don't take on much at once it works itself out. Otherwise it can get micromanagey when working cross-projects. With physical machines the can exactly work on one thing at a time, people might be optimal between 1 and 2. Technically you're still task switching one at a time but without the cognitive overhead of thinking about updating the tracker for multiple mid-day switches.