If I tell you on Monday that the plane will land by 3:05 on Saturday, and it is only Wednesday, and half the passengers aren't here, did I mislead you?
Equipment goes from not installed to installed. From not producing to producing. The more times they set up the same piece of equipment, the less ramp up each one takes. For all we know, they will be commissioned next week, and GF1 will be above 2,500/wk on the 21st.
Given the push back that statement got last time, I think is more likely that, worst case, they cut back next week's production so they can say: "Last week we made 2,500+ packs and 2,500+ 3s"