On a slightly related note, there is code in the EMF/WMF sections that snaps font sizes to the nearest .01 of a point. That and a few other similar actions were required to maintain numerical stability on import/export of these file types where drawing size is set in some number of pixels, typically on the order of thousands to tens of thousands. That limited precision would, without these optimizations, result in rounding errors causing these values to wander. With the optimizations "round trip" (open, change nothing, save with same name) results in exactly the same file, to the bit at the binary level. This made testing about 1000X easier because the numerical noise wasn't swamping out differences caused by code changes or bugs.
I don't know if other parts of Inkscape have similar code, but it is hard to imagine that similar numerical stability issues do not arise somewhere within the SVG context as well.
Regards,
David Mathog mathog@...1176... Manager, Sequence Analysis Facility, Biology Division, Caltech