This does not seem to be true, nor does it seem to measure from the center lines of the viewport. What it does seem to do is use pixels & measure from the 0/0 co-ord.The scroll sensor area left limit, defined as a percentage of the viewport's left half.
Valid values are in the range between 0 and 100; default value is 75.
Documentation Issue
Documentation Issue
In the "OpenSpace client-side configuration" documentation in the "Scrolling parameters" section the "ScrollLimit" explanation states
Jim Daniel