I implemented Bulat's idea for parsing with statistics moving forward.

That is, when you arrive at position "pos" you know the best way to arrive there, so you go back to the source of the best arrival and bring the statistics forward from there.

My LZA :

24700820 uncompressed

9267278 statistics carried forward (Bulat) (LZMA-style parse)

9315794 statistics updated only on 16k chunk boundaries (LZMA-style parse)

for reference :

9290222 old chain-N optimal parse at lowest level

9431777 7zip high profile