Marlin 3d Printer Tool question.. (no replies)

Is anyone familiar with using the "marlin 3d printer tool" ?
in the marlin tool, when i go to do the Z-Maintenance, it shows my maximum Z travel as 300mm, when i believe on the tevo tornado, it should be 400. it does not let you change that value on this screen.
any ideas ?
thanks,
kevin rea