Delta SkyMiles eliminated award charts. They charge you whatever they happen to want to charge you for a flight on a given day. SkyMiles aren’t like money, you can’t spend them anywhere you want (say for travel on American). It’s a company town, SkyMiles are their scrip, and they make no promises about what you should expect to get for your points in the future with a published price list.
A year and a half ago United made fun of the idea. However they’ve taken down the fulll .pdf award chart, and the interactive price tool doesn’t even display premium economy award prices at all.