After rebuilding my studio PC I have hunted high and low for this wonderous article that is the ultimate guide to Cubase MIDI problems, such as delay and notes playing early (which isn't actually latency, although most people, even the Cubase boffins, assume it is).
Its deep and its gooooood!
If your notes play early or late, then its all about the 2nd paragraph - tick the 'use system timestamp' box.
Easy peasy lemon squeezy!