AFAIK max spinup time is max life of agent (busy or idle) and max idle is maximum allowed time to be idle
max_spin_up_time_min
- the maximum time for an instance to spin upmax_idle_time_min
- the maximum time for an instance to stay up with worker on it (the time the ec2 instance is finished running a task with the agent and still up with an worker running on it listening to the queue)