This is a temporary thing because of automated payouts not working yet and the data about BTC withdrawn from exchanges is out of sync (because I don't withdraw them to the pool automated wallet yet, but to my own wallet on my computer). Until 20th Jan I was paying from my own money without waiting for coins to be exchanged, so the negative balance in “ready to pay” means “there were paid more than were withdrawn from exchanges”, which was correct on 20th Jan. The pool currently doesn't know how many BTC were withdrawn from exchanges after 20th.

So the negative balance is because I paid you more than was withdrawn from exchanges as of Jan 20th and the data of withdrawn coins wasn't synced after that. In reality, most of the unexchanged balance is already exchanged so it should be in ready for payout category.

The total balance is correct though. The difference is only some coins should be in different categories.

I'm just starting automated payouts so balances in particular categories will get sync soon.