Frank
as said before I dont know the reason Steve put an up/down button on that screen as there are no such buttons in Mach, you only have a button that will cycle through the increments.
You could as I said adapt a screenset and change the buttons to VB buttons, you would then open the screenset from the View menu and browse to your screenset (the one you just changed) and load it. You would then need to write some VB code into these buttons to do what you wanted.
I will not go into the details of this as you are starting out and it might just complicate things, once you gain experience with Mach and the way things work you can moive another step forward.
BTW I for one think you are doing the right thing by asking questions, if you dont ask you dont learn and even though the manuals have most of the info its written in a language you dont yet understand and believe me I know how that feels, I was in the same position as you 5 or so years ago
Hood