It is an interesting question. We have ran into similar situations where we are essentially make the same report over and over for slightly different aggregations. We never had to make multiple data sources though as we used Level of Detail expressions along with Dynamic Filtered ranges per sheet to show all the data on one dashboard with different date ranges/metrics. IE: on one dashboard, we have a rolling 3 year average compared to the last 6 weeks rolling and then also have a Year To Date on the same dashboard. Not sure if this is entirely similar but I do agree to simplify and not have excess extracts running is the way to go.