You also appear to have been using KOReader in scroll mode, which is just plain heresy ;o).
(I imagine that was to try to end up with alternating lines for the comparison, but that doesn't really work with a diff, IMHO. I'd be more interested with an overlay diff, in addition to an horizontal side-by-side).
In any case, this is meaningless without detailing the exact settings you've used on both sides, because you have a lot of footguns at your disposal in KOReader
.
(EDIT: And the font.)