The complete replacements are probably to avoid bspatch failures.
Plus, the overall total size should be smaller.

bsbatch was specifically design to yield a small size when used on an ELF file structure.
It doesn't do a very good job of minimizing the patch size on text files.
And their not bothering to update the firmware version is not new either.
2.5.8 is up to either 2.5.8.2 or 2.5.8.3 now by any sane numbering system.