Oh, note line 352, we start with True so we read the L=1024 vectors and we reach the L=2048, N=224 vectors which sets the reading_key_data to False then we go to L=2048, N=256 vectors which sets it back to True and it remains True when it reaches L=3072. They are in that same order in the vector file. TL;DR We skip the L=2048, N=224 case only.