Maybe you don't get my point. I think 3000+ users double check same hash numbers. I do not pretend I'm correct or that I understand. I just remember an old post of ByblePay saying multiple users "solved" same blocks in the pool.
Whatever is that botnet I think they use unique hash check code - it's open source. By my assumptions 100-200k unique hashes can beat our pool with 1 850 000 total hps. Anyway I continue to hoDL that machine in background HT cores with about 3100 hps. At some moment I'll hit 7000+ coins. Positive expectancy is because I'll not have fees and competitors aren't doing unique hash checks. If this is so then the most effective miner is solo machine. If I put 10 solo, then I'll increase the income by let's say 7 times not 10 (related to double hash checks between nodes).