Only way for this to work is to use 6 inputs and then get a Brain command to check and do the necessary work.
Problem here is you need another PP

In the normal method of one input for Z+ and Z- one switch can be home as well. It will work as you say hits the switch backs off and touches back onto the switch, that's part of Mach

And that's the most infuriating part, it knows this and can do this but Brian can't be arsed to get it to do the same with limits, preferring instead to piss about with fancy gee gaws that other 'want' and never use whereas this is a basic CNC application and should have been in years ago.

'Rant over '