[zip recompression: deflate->7z]
379,710,414 uncompressed (sh_samples_1 corpus)
166,440,588 zip(7zip)
131,893,109 7z

(166440588/131893109-1)*100 = 26.19%
(1-131893109/166440588)*100 = 20.75%


[.docx recompression: deflate->7z]
10,768,956  1      // .docx folder
10,769,695  1.7z   // archive w/o comression
93,933,057  1.pcf  // 1.7z processed with precomp
10,682,166  1b.7z  // archive with compression
 5,260,067  1a.7z  // 1.pcf compressed

(1-5260067/10769695)*100 = 51.15%
(10769695/5260067-1)*100 = 104.74%


[pdf recompression -> deflate->7z,jpeg->packjpg]
2      83,047,276 // .pdf folder
2.7z   83,048,509 // archive w/o comression
2.pcf 157,278,917 // 2.7z processed with precomp
2b.7z  79,221,963 // archive with compression
2a.7z  63,024,129 // 1.pcf compressed

(1-63024129/79221963)*100 = 20.44%
(79221963/63024129-1)*100 = 25.70%


[mp3 recompression -> mp3zip)
3      126,459,571 // .mp3 folder (random files, not an album)
3.7z   126,460,262 // archive w/o comression
3b.7z  121,110,590 // archive with compression
3a.mpz 101,706,411 // 3.7z processed with mp3zip

(1-101706411/126460262)*100 = 19.57% // gain vs uncompressed
(126460262/101706411-1)*100 = 24.33%
(1-101706411/121110590)*100 = 16.02% // gain vs lzma
(121110590/101706411-1)*100 = 19.07%