Depth Lock in V8i?

Version 08.11.09.459

I'm experiencing the following issue with a 3D model:

My steel structure is drawn at Z= +53.30m but when I click to draw a line in the elevation, the starting point of the line is at 0.00m and not at the position where I clicked. In the attached image I have highlighted my startng point with a red markup.

I know that depth lock no longer exists in Microstation so could it be a setting within Accudraw?

Can someone point me in the right direction?