Basically Razor's Pzlib is used to decompress and then compress it with lzma or other packers.
ex: the original file size x64a.rpf = 46.4MB
the i compressed with normal method srep+lzma size is 45.2MB
pzlib decompress the file streams then the file becomes 148MB and then i packed with LZMA , it becomes 36MB
these are testing images.