myStickymenu hide on scroll up to certain Y values

I am trying to implement this feature in plugin myStickymenu, so that the specific pane displays at scrolling down 500px (which works) and then hides again when scrolling back up to 1000px.

I understand this could probably be done by:

• Extending functionality using the custom CSS features. I have tried stuff such as

  #mysticky-nav .myfixed { margin:0 auto; float:none; border:0px;background:none; max-width:100%; }
  #mysticky-nav.wrapfixed.down {
      visibility:visible
  }
  #mysticky-nav.wrapfixed.up {
      visibility:hidden
  }
  

• Editing the plugin to add another option for disable on scroll up length (this is what I'm trying to work on now, but I have no experience editing WordPress plugins) This is what I have come up with so far, here. Pretty much just added the option so far and looking to how I would implement it in the scroll up code. I have left all original credits, comments and headers in as this will just be for my own personal use.

If anybody could assist it would be greatly appreciated!

Again, thank you.