That was the current schedule for 2016, so Model S and X only and wouldn't apply to the Model 3. Especially since they planned on making more 3's than S&X. It would only make sense that they would either have to increase automation a bunch (which apparently isn't working out) or hire more people (which would make adding a shift make more sense). Then again if automation was working great they still would likely have to add a shift as someone has to oversee the machines working, and it would make no sense to not have the machines work 24x7.
I wonder how badly that will affect any gross margin? Automation was the main reason Elon felt he could sell the model 3 for $35,000 at a profit and make it in the USA. The cards just got reshuffled.