Average PWR sell price shows the average price at which the MotherDAO treasury (3PQn4BwNW1kcX1gagVHWxSP5RyQ3V9UYPT8) has sold its PWR through swaps.

Average PWR buyback price shows the average price at which the MotherDAO treasury has bought PWR back from the market.

For the treasury contract's buyback operations to stay sustainable, the Average PWR buyback price has to remain lower than, or close to, the Average PWR sell price.

Both lines are all-time-to-date averages in WAVES per PWR, so each point is the average over every swap or buyback made up to that day rather than that day on its own.