With FEF, the speed you reach in the second burst depends how you enter the zone. If you slow down enough, you won’t reach near max, if you you coast through the E part without slowing down much, you might reach top speed.
The risk of entering the second zone too fast is that you might struggle to pick up speed. the key is relaxation. Check the GPP vid for examples of excellent form in all levels of speed from early GPP to late.