Question about the <max_step_size> in px4 SITL

hello everyone
I meet a question about the world files in SITL.
when I use UAV simulation in gazebo, the some parameters in world file are:


when I add other robot models such as manipulator in this world, the UAV works well, but other robots maybe work bad.
the main problem is:

<max_step_size> and <real_time_update_rate>

I konw px4 needs that:


but other robots or some plugins need:


I have a plugin (vacuum) on manipulator , and when the max_steo_size is 0.004, vacuum can’t work well.
I use vacuum by in xacro file, so I can not modify the parameters in .so file.

how can I fix this problem?