START_C not efficient

[Jonney3099]

For text of "12345Cabc" + '\n' + "aD" + '\n' + '\n' + "aEF", the most efficient is:
START_C 12 34 CODEB 5 C a b c CODEA \n SHIFTB a D \n \n SHIFTB a E F
or:
START_C 12 34 CODEB 5 C a b c SHIFTA \n a D CODEA \n \n SHIFTB a E F
The shortest is 20 Encoding words. But I get 21 words by GenCode128:
START_B 1 2 3 4 5 C a b c SHIFTA \n a D CODEA \n \n SHIFTB a E F

Look like START_C and CODE_C is not fully optimized.