I would expect that the target for a rewrite would be better known than the during the first write and that the morphing to hit a moving target would provide mo

I would expect that the target for a rewrite would be better known than the during the first write and that the morphing to hit a moving target would provide more opportunities for bugs. OTOH if there was a lot of pressure to get the rewrite done, that would be conducive to producing buggy code. I think management would be a bigger factor than any technical issues.