Currently there is no way to create a session that is this dynamic. The profile can only change the target temperature based on time, you can't control the other settings like On/Off or PID in the profile.
It sounds like you would just do a static session for step 1 using On/Off and then start a different static session for step 2 using PID mode.
We are working on a new session interface where you would be able to have the level of control that you are talking about over the unit. It won't be completed for a while though.