You're welcome. Thanks for starting on a topic that needs some analysis to help Steemians get better results.

If you look at the "Top Promoted Posts, by spending" chart, every bar where red portion is higher than the blue portion indicates a losing post - where author had spent more on promotion that yielded in rewards.

Aha...I see it now! I was more focused on the second chart, and then just looked around for negatives. The confirmation bias in action! Oops.