Question about server l2 lineage

Got question about server why we can't use the   second window ? "one window reached!" the other thing is that at evenings we have almost 14k online and we can't use 2 windows ok but  from that 14k online some ppl getting advantages if with pa acc its allowed to log boxes . sorry for english just need info about those 14k++ ppl at evenings cuz w/o box its sux to lvl up for example my overlord  so I hope that donators can't log those boxes...