When reading the y position of staff text it differs by 1.5 from the position it was written at.

When i write a staff text element as follows:
var newButton = newElement(Element.STAFF_TEXT);
newButton.text = "something";
newButton.pos.y = 20;
cursor.add(newButton);
and afterwards read out the y position of the element
var position = cursor.segment.annotations[0].pos.y
The position read is 21.5 rather than 20.
I have confirmed this with an adapted walk plug-in and the bug is consistent.