Custom line types appear different sizes at different scales.Product: MicroStation SE
Line styles do not always have to be the same, they can be set to different scales.
When you scale a linestyle, you are changing the size of the line styles. The scaling of dashed lines does not have to be the same.
To change the scale of the linestyles, go to:
Edit menu > Select By Attributes, and select all the linestyles you want to change.
Then go to
Element > Line Styles > Custom and set the Scale Factor you want.
Next, select the Change Element Attributes tool, and place a data point in space in the view window.
All the selected linestyles will now be updated.
http://communities.bentley.com/Products/MicroStation/w/Microstation__Wiki/setting-linestyle-scale-in-microstation-v8