Big overshoot in offboard mode for altitude

Hi,
I use ROS to control my quadrotor in offboard mode,and send 3m altitude setpoint to the vehicle.
I set MPC_Z_VEL_MAX_UP to 0.5,but it takeoff so fast,and rise to over 4m.
However,when i make it to land,it fly much slower than the velocity it takeoff.
Is it the problem of controll params?
This is my flight log.
http://logs.px4.io/plot_app?log=97d54360-babd-42ea-af53-354639e5742c

Try MPC_TKO_SPEED and MPC_LAND_SPEED for takeoff and land speed.