I picked the Last Round ROI because you are already calculating it :-)

I haven't watched enough to see how time of day affects ROI but I assume the 4 main US time zones have a big effect on bidding. If true, Last Round ROI would be an indicator of where bidding stands. 

A chart or trailing average or average for time/day would be more telling but as you confirmed, it is outside of the current scope of the app.

I also realized that this is more of an _investment_ than promotion tool except I'd rather get _free_ advertising than have to pay.

Thanks again!