But you're not writing software for production, you're writing software for understanding/advancing research. Every thing that doesn't match up is either a mist

But you're not writing software for production, you're writing software for understanding/advancing research. Every thing that doesn't match up is either a mistake on your end, or an undocumented (and possibly dubious) assumption on their end, and it's really valuable to find out either way. Reimplementation matter hugely (in ML at least). But that doesn't mean having the original implementation available isn't a huge advantage, obviously it is.