tl;dr Use the in-car nav screen to get the charging rates for a specific Supercharger site.
A month or more ago, Tesla changed to where individual stations can have a different rate than others within the same State. It’s no longer “all stations in Kansas are X cents”. There are a couple different rates used in Kansas. The only way I know to get the rate for a specific site is to get the station details on the in-car navigation system.
At the same time this happened, instead of giving you a drop-down menu on the web site with the rate charged within a state, they give a country-wide average on the web page.