As I understand it uses the Huffman-code for all moves including the opening moves. Alternatively statistics could be gathered for all first moves, all second m

As I understand it uses the Huffman-code for all moves including the opening moves. Alternatively statistics could be gathered for all first moves, all second moves, etc..., then different Huffmann-code could be applied for opening moves. I wouldn't be surprised if the statistics for the first few moves were significantly different to the moves deep into the game.