I don't have much knowledge of this information. I use the small bots to boost my posts and do not delegate. But here is one point.

If a bot does not have a lower limit for payout, and allows votes between 0-20 minutes - people will time things and post at a good time to get big votes in the first 15 minutes. This changes the curation % and so the author can get 90% of the reward and the curators will only get 10%. This type of voter does not care about payout percentages - only the $$$ value of the upvote counts. The more they get in the value of upvotes in the first 15 minutes, the less the curators get at payout.

This is due to steemit's way of doing math somehow. On some of those bots, 2-3 people at a time will jump in big at the last minute and the payout on the bot will be really, really low. Some of these people will bid 80% of the bot value as a regular habit. So the bot earns better money for the delegators.

Jerry's bot used to take bids in 0 minutes and did not have a lower limit. I keep him on my https://steembottracker.com/ list even though I never use his bot. Without the lower limit, his bot used to crash hard all the time. I'm talking negative 50% or more.

I came in with Jerry last year and I know him. He helped me with upvotes before he started his bots. So I reached out a few weeks ago and told him how this situation was going down and he put a lower crash limit of 10%. So his bot will never crash that hard again and the payouts to delegators will be less. Any numbers before two weeks ago no longer apply to his bot. The people with this strategy will also not be bidding on his bot for the most part. If they do, it will be a smaller, more logical bid.

In my case, I try to bid pennies and get 70% or more payout. I do not use the bots at all in the first day except for one that only votes in the first 24 hours. I have a plan and work it and get maybe $2-$5 extra on most posts. I'm doing it for the sp, the sbd, and to reward my regular voters better.

As I said, I had Jerry on my list, because I could tell when the bad guys are bidding as there are also some of the smaller bots they use for this too. I don't want to be there with them and their negative return if I can help it. But Jerry's bot no longer serves that purpose for me with the change he made.