Hey @joeparys, you were looking at ROI of the last round most of the time that's why they were negative. Click on the current round button if you want to see for the ongoing vote.
Like for postpromoter when you looked at it was showing 164% ROI because you were looking at current round. But when you looked at it again it was showing negative because that time you were looking at Last rounds number. So be sure to click on current round next time.
I have been studying the ROI of different bots for the past weeks and some are better than others.
Also you should not Transfer huge amounts of SBD like 50+ to a single bot that has maximum upvote of around a 100SBD because the ROI you see on the Current round is the one before you placed your own bid.
Lets say for example a bot A has max upvote of 100SBD and its showing 100%ROI then that means already 50SBD has been bid on that bot. And if you add your own 50SBD on that bot it will instantly go 0% ROI because now 100SBD has been bid so look for bots that have high ROI above 100% and bet lesser one-third or half(lesser will be more profitable) of what is shown in Max Profitable bid.

One more thing, the number you see on steem bot tracker are not 100% accurate (but they are very close approximates) and it better to wait until the Last 5 minutes to place a bid.

Hopefully this has been helpful, I started using bidding bot since last week after I looked at another one of your post, Thank you.