Explanation for example for 7.6.2.1.2 Serial composition seems incorrect

The explanation for this example says:

This suggests that the speed during phase 2 may vary between 10 and 15 kph, which is not the case. One single value for the speed is chosen before the start of the action and then kept constant during its entire execution. If the motion should be continuous without any jumps in speed, 10 kph would be the only valid value since that's the value the previous action ended with.