I will try taking a look at this later today.
Is the issue primarily the difference in spacing?
Changes were made to spacing which would affect voffset in the preview phase of 2.1, etc. This was done to make spacing more consistent. See the following thread related voffset which might provide some additional insight on this.
In terms of the voffset spacing, it is in pixels so assuming correct scaling of the camera, etc. a value of 3900 would be 3900 pixels which is massive. If you need the value to be relative to the point size of the text, then I would use an em value instead such as <voffset=1em> where assuming the point size is 100 would represent 100 pixels. if the point size was 50 than 1em would be 50 pixels.