By a half bend you do literally mean a half bend right? Not that you're just bending it a little bit?
If you're using Bendometer and have the layout set to "Bends" it should only show the half step as you can't bend that note any further.
ie. For a C harp there should be a box below hole four with a D in it, and a box below that with a C# in it.
If you mean you can bend down to C# then great, that's all you need to do. If you mean that the blue box which shows how far you're bending only gets half way then keep practicing!
Kennyp, a Bendo Meter is a software one can use (provided you have a microphone) that will show you on you monitor if you are bending the notes and how far you are bending them.